How to Compress Images Without Losing Quality

A 4MB photo straight off a phone camera is overkill for almost anything you'll use it for online — a product listing, a blog header, a WhatsApp Status. Compressing it isn't really about making the image worse, it's about throwing away detail your eyes were never going to notice in the first place.

Lossy vs lossless, in plain terms

Lossless compression (like PNG) squeezes the file without discarding any pixel data — you get a smaller file, but only up to a point, and photos barely shrink at all this way. Lossy compression (like JPG or WebP) is where the real size savings happen: the encoder identifies detail that's hard for the human eye to distinguish — subtle color gradients, high-frequency noise — and discards it. Done well, a photo compressed to 20% of its original size can be visually indistinguishable from the original at normal viewing size.

What actually causes visible quality loss

• Compressing the same file multiple times (each pass throws away more detail — always compress from the original, not from an already-compressed copy)
• Pushing quality settings too low in a rush to hit a specific file size
• Compressing images with fine text or sharp graphic edges the same way you'd compress a photo — text and logos hold up much better as PNG
• Resizing and compressing in the wrong order — always resize to your target dimensions first, then compress, not the other way around

A sane approach

For photos: aim for a quality setting around 75–85% — this is usually the sweet spot where file size drops sharply but quality loss stays invisible at normal screen sizes. For screenshots, logos, or anything with flat colors and text, keep it as PNG or convert to WebP instead of JPG — JPG's compression artifacts are much more visible on sharp edges. See the full format comparison for when to use which. If you're preparing images for a website, compress after you've resized to the dimensions you'll actually display — there's no reason to compress pixels you're going to throw away anyway.

Digy's compressor handles the quality tuning for you, aiming for that visually-safe middle ground automatically, entirely in your browser — nothing gets uploaded to check.