Large images slow down ordinary tasks
A photograph straight from a phone can be much larger than a website, email or form needs. The compressor reads the selected file in the browser, draws it to a canvas and creates a new copy. The default WebP output and practical quality setting often reduce photographic files without asking the user to understand codecs.
Quality changes the encoded copy
JPEG and WebP use lossy compression. Lower quality usually produces fewer bytes, but fine texture, text and sharp edges may become less clear. PNG uses lossless encoding and ignores the quality control. The tool shows the processed preview and real output size so the decision is based on the file it actually created.
The original is never replaced
The browser creates a separate downloadable result. It does not modify the source file on disk. Keep the original, inspect important details at full size and download only when the new copy suits its destination. A negative percentage means the result is smaller; a positive value means the chosen format increased it.
Transparency and format matter
WebP and PNG can preserve transparency. JPEG cannot, so transparent areas receive a white background when JPEG is selected. Logos and interface graphics may remain sharper as PNG or SVG, while photographs usually respond better to WebP or JPEG. Changing formats is not automatically an improvement.
Processing stays local
The file is decoded and encoded with browser APIs. It is not uploaded to this site, stored in an account or sent through an image service. Browser support determines which source formats can be read and which output formats can be created.
A practical check before publishing
Open the result at its intended display size and inspect faces, text, gradients and areas with fine detail. Compare it with the source instead of judging the file-size number alone. For a website, confirm that the HTML or image component supplies suitable dimensions and responsive sources. Compression helps delivery, but it does not replace correct sizing, caching or accessible alternative text. If the new format is larger, keep the original or try another setting. The smallest possible file is not useful when visible artifacts damage the image or the destination cannot read its format.
What this compressor leaves out
It does not batch-process folders, remove a background, preserve animation or upload a finished asset to a content system. Those additions would make the first task harder and may require server storage. The current boundary is deliberate: choose one ordinary image, create a smaller copy, see the real comparison and decide whether to download it.