Resize WebP images

Use static WebP where the receiving workflow accepts it

A format that works in your browser may still be rejected by an upload form or an older editing workflow. Check the destination before choosing WebP. For a supported still image, decide its dimensions, transparency and acceptable encoding quality, then inspect the resulting file. Compare candidates using the same subject and display size. A smaller WebP can be useful, but no fixed saving applies to all images.

This editor supports static WebP, not animation editing. A container with multiple frames needs a workflow that preserves its timeline rather than quietly retaining a single frame. The format choice also does not replace review of transparent edges or small text. Open the downloaded WebP in the application that will consume it, because that acceptance is part of the task.

One side, two limits or a percentage?

Width-only sizing is convenient when the final height is flexible. Two-sided fit is convenient for a mixed collection that must stay within a common maximum. Percentage sizing is convenient when you want the same scale reduction for each source. A 50% width and height does not mean 50% as many pixels: it leaves 25% of the original pixel count, because both sides shrink.

For example, 4000 × 3000 at 50% becomes 2000 × 1500: 12 million pixels become 3 million. This calculation says nothing exact about the JPEG byte reduction. Also check rounding on odd dimensions. The result is an integer pixel grid, so a computed fraction of a pixel must be rounded. Read the measured output instead of expecting every ratio calculation to land on whole numbers.

Transparency needs a format and a background decision

Transparent space is not white space. An alpha channel records how opaque each pixel is, including soft edges around a logo or illustration. PNG and static WebP outputs can retain this channel. JPEG cannot: the image must be composited onto a background. Choose that background deliberately, especially when the final page is dark or the artwork has pale lettering.

Inspect edges against both light and dark surfaces. A logo that looks correct on white can reveal a halo on navy. Padding has the same choice: keep its empty space transparent, or fill it with a chosen color. Once alpha has been flattened into an opaque file, switching the extension back to PNG cannot reconstruct the missing transparency. Return to the transparent original instead.

Quality is a control, not a percentage of perfection

A JPEG quality value of 85 does not mean that 85% of the source survives. It is an encoder setting, and its visual effect depends on the image and the encoder. Start with a moderate high-quality export, inspect important details, then lower the setting only as far as your use case allows. Skin, hair, small lettering, foliage and smooth gradients are useful places to look for artifacts.

Dimensions and quality solve different problems. A 4000 px photo at very low quality may contain lots of pixels but weak detail. A 1000 px photo at high quality may look clean at its intended size but cannot supply a large print. Choose a sensible pixel grid first; then use quality to control encoding. Even quality 100 is not a guarantee that a JPEG export is lossless.

Meet a byte ceiling without hiding the tradeoff

A maximum file size is an acceptance rule: the result must not exceed a ceiling. It does not require the output to weigh exactly that amount. This editor uses decimal units, so 100 KB means 100000 bytes and 1 MB means 1000000 bytes. A result of 98200 bytes meets a 100 KB limit; 100001 bytes does not. Those values explain the rule, rather than predicting what your photo will produce.

For JPEG and WebP, the tool can try different quality values. If the limit still cannot be met, a fit-mode job can reduce dimensions only when you explicitly allow that. Exact crop and padding canvases remain fixed. PNG follows a different path because its encoding is lossless here. An unreachable combination should lead to a clear warning and a revised requirement, not a secretly changed format or chopped-off subject.

The download is the final test

A preview is helpful, but the saved output is what the receiving app will use. Check its actual dimensions, MIME type and exact bytes. Open the file in an image viewer, inspect the important details at a sensible scale, and confirm that transparency or the chosen background behaves as expected. If you created a ZIP, open it and compare its successful entries with the expected count.

When a result fails, change the constraint that is actually responsible. Wrong shape calls for a geometry decision; unreadable text calls for more detail or less aggressive encoding; excessive bytes call for a permitted compression or dimension change. Keep each candidate separate until you choose the final one. The original remains your reliable starting point for every new export.

1. Check the real width and height, not only the requested box.
2. Compare exact bytes with the destination’s ceiling.
3. Inspect faces, lettering, product edges and transparent boundaries.
4. Save the chosen output and keep the original separately.