Use JPEG for everyday photographs
JPEG uses lossy compression: it discards some image detail to reduce file size. It suits photographs with gradual changes in color. JPEG cannot preserve a transparent background. PNG uses lossless compression and supports transparency, making it useful for screenshots, diagrams, and graphics with sharp edges. WebP supports both lossy and lossless compression, plus transparency; the encoder determines which options are available.
For a product photo on a plain background, export a JPEG and inspect the edges of the product. For a portrait, look closely at hair and skin texture. Choose a setting that keeps the details you need at the size the image will actually appear.
Further reading: MDN: image format features
Keep PNG for crisp graphics
A screenshot of a spreadsheet is a different problem from a holiday photo. Small text, thin lines, and flat blocks of color make slight changes easy to notice. Try PNG first for those images, then compare a smaller alternative if your destination supports it.
For a logo with a transparent background, preview the result on both a light and a dark surface. If you need JPEG, choose a background color before exporting. The checkerboard in an editor represents transparency; it should not become part of your final picture.
Try WebP when the destination supports it
For website images, compare a WebP export with your JPEG or PNG version. Look at both appearance and file size. A format change alone does not guarantee a smaller file, so keep the version that best meets your actual needs.
Before converting a whole collection, upload one sample to the platform or open it in the application you plan to use. Check any published file requirements. An image that opens in your browser may still be rejected by a particular form, publishing system, or editing workflow.
Start with the file you have
Toolzorix can open HEIC and HEIF phone photos, still AVIF images, and static self-contained SVG artwork, as well as JPG, PNG and WebP. These additional input formats do not become extra output choices: use JPG, PNG or WebP for the converted picture. HEIC decoding happens on your device; AVIF requires a browser that can decode the file.
SVG to PNG turns vector artwork into pixels at a fixed size. Keep the SVG for later path edits or larger exports. PNG to ICO serves a different purpose: choose a square icon size from 16 to 256 pixels. This tool fits the artwork inside the square with transparent padding and writes one PNG-compressed icon image per ICO download.
Make one export, then check the result
Keep an untouched original and make each trial from that file. Use descriptive filenames such as product-front-web.webp so you can tell exports apart. Compare the downloaded image with the original at the same display size, paying attention to text, edges, and background color.
If the file is still too large, check its dimensions before reducing quality further. A smaller image at the right size can be more useful than a full-size image with visibly damaged detail.