Picking the right image file format—like JPG, PNG, SVG, or GIF—can make a big difference to your website’s speed, SEO performance, and visual quality. But with so many options available, it’s easy to feel overwhelmed. What’s the best format for product photos? How does file type affect loading times or image sharpness on mobile? And which formats work best on social media?
If you're managing visual assets for your brand or ecommerce store, understanding image formats is essential. The right choice helps you:
- Speed up page load times
- Preserve image clarity and transparency
- Improve search engine visibility
- Optimise content for social sharing
In this guide, we’ll break down the most common image formats—JPG, PNG, SVG, GIF, and RAW. You’ll learn when to use each one, how they impact performance, and how to optimise them for best results.
TLDR: Different image types and what they’re best for
Note: You’ll see each image format has a compression type of lossy or lossless.
- Lossy formats (like JPEG) shrink file size by removing some data—fine for web and social, but not ideal for editing or print.
- Lossless formats (like PNG or TIFF) keep all the detail, so they’re better for storing originals or high-quality assets.
What’s a JPG?
JPG (or JPEG) is a compressed image format using lossy compression. It's ideal for web photos when you need a balance between quality and fast load speed.
The JPG (or JPEG) was first created by the Joint Photographic Experts Group back in 1992 (hence its name). They’re a committee of people who want a way to make high-quality and large image files smaller and easily shareable on the web.
It means that marketers and content creators using complex images on the web can consistently meet image compression standards (and don’t end up with a horrible pixelated image that makes you wanna 🤮).
That being said, you can expect to lose a level of quality when compressing high-quality images into JPEGs. That’s because JPEG files use lossy compression, meaning some is removed data from the original image file. That results in the file being smaller and therefore quicker to load on the web. However, it's important to note that too much compression will hinder its quality.
When should you use a JPG image?
JPGs are recommended when you need a balance between quality and file size. For example, if you’re uploading a photograph into a blog post, a JPG will ensure you don’t slow down the loading time of said article.
What’s a PNG?
PNG stands for Portable Network Graphics and is a high-quality image format using lossless compression. That means it doesn’t lose any of its information on compression, so image quality is usually much higher (and the file size much larger) than its JPG cousin.
When should you use PNG formats?
Typically, people use PNG formats for graphics (such as logos), text objects, and line drawings. It also supports transparency, which is super handy if you need to place a cut-out logo against a different background.
A PNG offers a lovely, crisp image, but it does slow down web pages. So make sure you’re weighing up speed vs quality when you’re updating your online store.
PNG vs JPG: Which provides better image quality and compression?
When you’re choosing between image formats, it really comes down to two things: quality and compression.
PNG files use lossless compression, which means they keep all the original image data. Great for crystal-clear visuals — but not so great for file size. They’re heavier, which can slow down your site if you’re not careful.
JPEG files, on the other hand, use lossy compression. They ditch some of that image data to shrink the file size — which helps your pages load faster. You might lose a bit of sharpness, especially if you compress them too much, but for most ecommerce use cases, the quality still holds up.
Our tip: PNG gives you the sharpest image, so it’s ideal when detail matters. JPG gives you speed, so it’s perfect when load time is the priority. Most of the time, a well-optimised JPG will strike the right balance.
PNG vs JPG: which is better for website loading times and file size?
As an ecommerce brand, you already know that fast-loading pages = better conversions. But bulky image files can quietly drag your site down, especially if you’re using high-res PNGs across your homepage or product listings.
Now, don’t get us wrong. PNGs are great when you need super-sharp visuals or transparent backgrounds (like for logos or UI elements). But they come with bigger file sizes, which means slower load times — not ideal when you're trying to impress a new customer or rank higher in Google.
That’s why a JPG is often preferred. They use lossy compression to keep file sizes low, making them perfect for product photos, blog images, and lifestyle content where transparency isn’t needed. Yes, you’ll lose a tiny bit of quality — but for most use cases, it’s barely noticeable (especially if you compress images properly before upload).
💡 Our tip: We recommend using PNGs sparingly and and only when transparency or razor-sharp detail is a must. For everything else? Stick with optimised JPG photos or try WebP for even faster performance.
JPG vs PNG: Which file formats are better for social media?
Both JPG and PNG formats are supported across all major social platforms — so technically, either will work. But the problem is that platforms like Facebook will automatically compress your image to fit their specs. And if your file isn’t sized correctly, you might end up with a blurry or pixelated post.
To keep things crisp, always upload images at the correct dimensions for the platform you’re targeting. That way, you stay in control of quality — not the algorithm.
💡Dash tip: When you store your content in Dash (our digital asset management solution), you can crop and resize to social media specs on download. It means you can prepare content for your channels quickly, without hassling your design team.
What’s a GIF?
GIF (sometimes pronounced as jiff) stands for Graphical Interchangeable Format. It was invented as a way to display moving images on the web with minimal file size. Rather than displaying a video, it’s more like a flipbook that moves between different images. Each image can only use a maximum of 256 colours, but it means the file’s small enough to show up on different channels across the web.
When would you use a GIF?
GIFs have gained in popularity over the years and you’ll most likely see them on social media. However, you could also use them in blog posts (like we do), embedded into emails or sent over instant messaging platforms like Whatsapp. They’re a great way of conveying an emotion or referencing something from your favourite TV show without needing to send over a YouTube link.
What’s an SVG?
SVG stands for ‘scalable vector graphic’. To understand how SVGs differ from other file types, we need to look at how they’re made up.
A JPG or PNG are types of raster graphics. This means they're created using lots of little pixels in a square called a bitmap. Combined together, these squares form an image. This is great for displaying photographs and high-quality images because each square can match the colour of the RAW file. However, it does mean that the bigger the file, the lower the quality.
SVGs, on the other hand, are coded. They’re written in XML format, and you can literally code up the colours and shapes that you want to appear. It also means that no matter the size of the graphic, you’re still going to get fantastic quality.
When would you use an SVG?
SVGs are typically used to create logos, illustrations and graphics. You can create your own SVG files by using tools such as Illustrator, Photoshop or Canva. Simply create a design using shapes and lines and export it as an SVG file.
What's WebP?
WebP was originally created by Google to replace PNG and JPG. It's a way of compressing a file without losing quality, and Google developers claim it's 26% smaller than PNGs. It also supports transparency and animation - making it a worthy competitor of the trusty GIF.
WebP is supported on most browsers including Google, Mozilla Firefox and Microsoft Edge.
When would you use a WebP file?
Need a quality image but don't want to sacrifice load speed? WebP could be your ideal choice. You will see some loss in quality however, so bear that in mind if you're working with high-quality pics from your photographers.
What’s a RAW file?
RAW file formats store absolutely tonnes of detail about an image. In fact, it has the most information about an image out of any other file format. It’s the data that’s captured in a camera before being compressed and sent off into different areas of the web.
When would you use a RAW file?
As a marketer, it’s unlikely you’d ever use a RAW file. They’re just too big to use on the web. That’s why many photographers use image software to edit and compress them into JPGs or PNGs before sending them over to their clients. If you’re taking your own photography, it's likely you won’t be shooting in RAW unless you’ve got specific settings turned on.
How your image format impacts SEO and website performance
Choosing the right image format isn’t just about how your visuals look. It plays a big role in how fast your website loads — and that can make or break your search rankings, bounce rates and your sales.
Large PNG files, in particular, can slow down your site if they’re not properly optimised. And, because Google prioritises speed as a key factor in its ranking algorithms, a slow-loading page might push you down in search results.
But it isn't just about SEO. Speed is especially crucial for ecommerce brands because when a customer lands on your product page, they expect it to load quickly and smoothly. If your page takes too long you risk losing that customer to a faster competitor. One study shows that increasing your load speed by just one second can increase conversion rates by 17%!
But don’t worry, choosing the right image format is one of the easiest ways to improve load speed without sacrificing quality. Tools like Dash (that's us!) make it easy to manage, resize, and optimise your images, so you always have the right format ready to go — without needing to juggle extra software or worry about slowing down your storefront. Scoot down for more tools that will help you optimise your images.
How to measure the impact of your images on web performance
If you want to see how your images are affecting your website’s performance, Google's Core Web Vitals are a great place to start. You’ll find them on Page Speed Insights Core that measure real-world user experience, with a strong focus on load time and responsiveness.
The key metric you’ll want to pay attention to is Largest Contentful Paint (LCP). This measures how long it takes for the largest piece of visible content — often a banner image or product photo — to load on a page. If your images are too large or poorly optimised, your LCP score will suffer, which can hurt both your SEO rankings and customer experience.
You can check your Core Web Vitals easily using free tools like:
- Google PageSpeed Insights (just enter your URL for a full report)
- Lighthouse (built into Chrome Developer Tools)
- Google Search Console (under the ‘Core Web Vitals’ report)
These tools highlight whether images are slowing down your pages and often suggest specific improvements, like compressing files or switching to formats like WebP.
5 tools to optimise your images
To get the best performance from your images, you’ll want to optimise your images before adding them to your site, marketing emails or ad campaigns.
Optimising means shrinking the file size without sacrificing how your images look. It helps your pages load faster, improves SEO, and creates a better experience for your customers.
Here are some of the best tools to make it easy:
1. Dash
If you’re looking for a simple way to create optimised, web-ready images for your ecommerce site, Dash makes it easy. You can quickly resize, crop, and compress your images so they're ready for your website, social media, email campaigns, and ads.
This is what it looks like to resize and optimise an image in Dash.
You can use preset sizes (for social media) or add your own. You can also pick whether you want the file to be downloaded as a JPG, PNG or WebP.
But Dash is much more than just an image optimisation tool. It's a fully-fledged digital asset management (DAM) platform designed to help ecommerce brands stay organised and scale their content workflows. With Dash, you can store all your visual content safely and add custom metadata and tags to keep your assets searchable. You’ll also be able to search content based on the type of file, create different versions for different channels, and easily share visuals with your team or external partners — all from one simple, intuitive platform.
Learn more about Dash’s digital asset management features.
Best for: Ecommerce brands who want fast, optimised images for every channel — and a smarter way to manage their entire content library as they grow.
2. TinyPNG
TinyPNG is a free, browser-based tool that compresses PNG and JPG files quickly without noticeable quality loss. It’s great for quick uploads or when you need to batch-process a handful of assets.
Best for: Fast compression when you’re prepping images manually.
3. ImageOptim
For Mac users, ImageOptim is a simple drag-and-drop app that automatically compresses images with minimal fuss. It’s ideal if you’re preparing lots of files at once and want to keep quality control in your own hands.
Best for: Bulk compression with minimal setup.
4. Shopify’s Built-In Optimiser
If your ecommerce store runs on Shopify, good news: Shopify automatically compresses your images when you upload them. It helps maintain fast load times without needing separate optimization steps.
Best for: Ecommerce stores looking for a simple, hands-off solution.
💡It’s also good to note that Dash integrates with Shopify, so you can optimise and resize your images before you drop it into your product pages.
5. Squoosh.app
Built by Google, Squoosh is a free online tool that lets you compress images manually while comparing quality before and after. It gives you lots of control over file size, compression type, and format — ideal if you want to tweak your images just right.
Best for: Fine-tuning compression settings for perfect balance between quality and speed.
Where should I store all my image formats?
Need a JPG for a blog, a square crop for Instagram, or a WebP for your product pages? With Dash, you can resize, crop, and convert your images at the point of download — no extra tools needed and no bothering your designer.
This is a game-changer for fast-moving ecommerce teams. Take Passenger Clothing, for example. Their team uses Dash’s built-in cropping tool to quickly reformat product shots for their online store. It speeds up their workflows and cuts out unnecessary design bottlenecks.
But Dash does more than just reformatting.
You can:
- Store every file type — JPGs, PNGs, SVGs, GIFs, WebPs and more — in one searchable library
- Add tags, metadata and custom fields to keep assets organised and easy to find
- Create public portals so your retailers self-serve content for their campaigns
- Collaborate across teams without clogging up inboxes or losing track of versions
Whether you’re launching a new campaign or updating product listings, Dash helps you move faster and stay in control of your brand’s visual content.
🚀 Start your 14-day free trial today — no credit card needed.
Amy Burchill is the SEO and Content Manager for Dash. She works with ecommerce experts to create articles for DTC brands wanting to improve their campaigns.
