Change Image Quality

A change-image-quality tool lets you re-encode a JPEG or WebP image at a chosen quality level so you can trade file size against visual fidelity on a sliding scale. The quality value, commonly expressed from 1 to 100, controls how aggressively the encoder discards information the eye is least likely to notice. Higher values keep more detail and produce larger files; lower values compress harder and shrink the file but can introduce visible artifacts like blockiness around edges or banding in smooth gradients. This tool decodes your image with the Canvas API and re-encodes it at the quality you pick, updating the estimated output size live as you drag the slider, all inside your browser with no upload. A crucial point is that quality compression is lossy and not reversible: once you re-encode a JPEG at a lower quality, the discarded detail is gone, and re-encoding an already-compressed JPEG repeatedly causes generational loss that accumulates with each save. For that reason it is best to compress from the highest-quality source you have, in a single step, rather than nudging an already-shrunk file. For most photographs a quality around 75 to 85 hits a sweet spot where files are much smaller but artifacts are hard to spot, while logos, text, and sharp graphics need higher settings because compression artifacts show up clearly against clean edges. Note that PNG is lossless and has no quality slider in the usual sense, so this tool targets JPEG and WebP, where a quality parameter genuinely applies. Common uses include hitting an upload size limit, speeding up a web page, emailing photos, or batch-shrinking images for storage. Everything runs locally, so it is fast, private, and works offline once loaded.