Understanding web assets for a digital archive

A folder of web assets can contain JPG photos, PNG graphics, WEBP images, GIF animations, and icons, all mixed together. It can be tempting to convert everything to one format, but changing files can discard details or reduce image quality.

For a digital archive, keep the files you received as your originals. Make converted copies only when you need them for easier viewing or sharing. The Image Converter can convert common image formats in your browser, but it does not convert CSS, JavaScript, fonts, or other non-image files.

Prepare web images for an archive

1. Make a separate working copy of the folder. Keep the supplied files unchanged, including their names and folder structure, and do not overwrite them with converted versions.
2. Check the file extensions and open a few examples. An extension such as .webp or .png is a useful clue, but it does not tell you everything about an image's history or quality.
3. Open the Image Converter and add up to 50 image files from your working copy. It supports JPG, PNG, WEBP, GIF, BMP, ICO, and TIFF.
4. Choose an output format based on how you will use the copies. Convert a small sample first if you are unsure, especially when the source includes transparency or animation.
5. Check the converted files and record what you did. Keep the source filename, output filename, format, and reason for conversion in a simple archive note or spreadsheet.

Use clear names or a separate folder to distinguish access copies from originals. For example, keep the supplied file in an originals folder and place a JPG or PNG viewing copy in access-copies. Follow your archive's naming rules if it already has them.

What the image formats mean

JPG for photographs

JPG is widely supported and often makes photographs much smaller than uncompressed formats. It uses lossy compression, which means some image detail is discarded when the file is saved. Converting a JPG to another format does not restore detail already lost, and saving it as JPG again can reduce quality further. Keep the original JPG untouched.

PNG for graphics and transparency

PNG uses lossless compression, so it preserves the image data it receives. It is a practical choice for graphics with sharp edges or transparent areas. A PNG copy made from a JPG cannot bring back the JPG's lost detail, though, and it may take up more space.

WEBP for web delivery

WEBP is common on websites and can store still images or animation. It is often compact, which makes it useful for web delivery. Keep WEBP originals if they are part of the material you are preserving. Make another format only when a viewer or archive workflow needs it.

GIF for simple animation

GIF can contain multiple frames, so it may be an animation rather than a single picture. A conversion that produces a still image may not preserve the movement. Check animated files before choosing an output format, and retain the original GIF when the animation matters.

TIFF, BMP, and ICO for specific uses

TIFF is used for images in some publishing and archival workflows, but a TIFF extension alone does not guarantee that a file is an archival master. BMP files can be large, and ICO files are used for icons and may contain several icon sizes. Keep these originals unless you have a clear reason and an agreed process for making a different copy.

Keep conversions from becoming the only record

A format change can affect compression, transparency, animation, color, and metadata. Metadata is information stored with a file, such as its creation date or camera details. The result depends on the source file and the conversion process, so do not assume that every detail survives unchanged.

• Preserve the received file. Treat it as the source, even if it is inconvenient to open. Do not replace it with a more familiar format.
• Make copies for access. A smaller JPG may be convenient for a website or quick preview, while a PNG may suit a graphic that needs transparency. These copies are for use, not substitutes for the original.
• Keep context with the files. Save relevant descriptions, source information, and any rights or usage notes alongside the archive records. Do not rely on image metadata as the only place for important information.
• Check the result. Open the converted copy and compare it with the source. Look for missing transparency, changed colors, lost animation, or unexpected dimensions.

If your archive has preservation requirements, follow its approved formats and documentation rules. Long-term preservation is more than choosing a file extension: it also depends on keeping copies safe, tracking changes, and checking that files remain usable.

The Image Converter works with image files in your browser. The files you open and convert stay on your device.