Web assets for a website speed upgrade

A website can feel slow even when your internet connection is fine. Large photos, unnecessary image dimensions, and files that load before visitors need them can all add delay. If you are preparing a speed upgrade, start by checking the assets the page actually uses instead of converting every file at random.

The Image Converter can convert up to 50 images at once in your browser. Use it to compare formats and make a lighter copy, then replace the original only after checking the result on your page.

Review and convert the image assets

1. Open the Image Converter and make a working copy of the images used on the pages you want to improve. Keep the originals somewhere safe so you can restore them.
2. Find the images that matter most. Check your site editor or media library for large files used near the top of a page, such as the main banner, product photos, or a large hero image. Note each file's dimensions and size in kilobytes or megabytes.
3. Choose a format based on the image. Photos are good candidates for WebP or JPG. Images that need transparency can use PNG or WebP. A logo that is already an SVG should usually stay in SVG, since the Image Converter does not convert SVG files.
4. Convert a small group first. Choose the output format in the converter, then compare the new files with the originals. Check both file size and appearance. If the new file is larger or looks worse, keep the original format.
5. Replace the files on a test page or draft, then check the page on a phone and a computer. Make sure the image is sharp, the crop is right, and the page still looks correct before updating the live site.

Changing a file format does not automatically make it faster. The best result depends on the original image, its dimensions, and how it was already compressed. Keep a simple before-and-after note with the filename, dimensions, format, and file size so you can tell what actually helped.

What the results mean

The converted image is smaller and still looks good

This is a useful candidate for the site. Smaller image files generally take less time to transfer, especially for visitors on mobile connections. Check that the image is not being stretched beyond its pixel dimensions and that the page uses the new file, not the old one cached by your browser.

The converted image is the same size or larger

Conversion is not a guarantee of smaller files. The original may already be well optimized, or the new format may not suit that image. Keep the smaller version only if it looks acceptable. If the files are close in size, prefer the format your website platform handles reliably.

The image looks blurry or has visible blocks

The output may have too few pixels for the space where it appears, or the conversion may have reduced image quality. Do not use a small thumbnail as a full-width banner. Find a larger source image, or create a correctly sized version in your site editor or image editor before converting it.

The page is still slow after image conversion

Images may not be the only cause. A large background video, web fonts, scripts, a slow server, or third-party content can also delay a page. If the converted images are smaller but the page still feels slow, investigate those other parts rather than repeatedly converting the same files.

Make the changes count

1. Resize images to the space they occupy. A 4,000-pixel-wide photo used in a 700-pixel-wide content area can waste bytes. Create versions close to the largest display size you need. If the page serves different image sizes for phones and desktops, use your site's responsive image options rather than one oversized file.
2. Keep the original files. Save a copy before replacing assets, and change a few files at a time. If a product image becomes soft or a transparent edge turns jagged, you can restore the previous version without rebuilding the whole page.
3. Load below-the-fold images later. If your site platform offers lazy loading, use it for images that appear farther down the page. Do not delay the main image visitors see immediately. Loading that image late can make the page seem slower even if the total download is smaller.
4. Use descriptive image dimensions. Set an image's width and height in your site editor when available. This helps the browser reserve space before the image arrives, reducing unexpected movement as the page loads.
5. Check the page after publishing. Clear or bypass the browser cache if you keep seeing the old image. Review the page on a phone and desktop, then check the actual file loaded by the page if your platform has a preview or network inspection tool.

Choose formats for the job

Use JPG or WebP for photographs, where smooth color changes matter more than a transparent background. PNG is useful for graphics with crisp edges or transparency, though it can be larger than a photo format. WebP can support transparency too, so it may be worth comparing for a transparent image. Keep SVG logos and icons as vector files when possible. They scale cleanly and are not supported by the Image Converter, so do not turn them into a large raster image without a specific reason.

Animated GIFs can be heavy, particularly when they are large or long. Converting a GIF to a still-image format removes the animation, so check what the image is meant to do before changing it. For a moving banner, consider whether the animation is needed at all and whether your site has a more suitable video or animation option.

Conversion only addresses image files. It does not reduce the size of scripts, stylesheets, or fonts, and it cannot make a slow server respond faster. The Image Converter processes the images in your browser, and the files stay on your device.