How to Compress an Image Without Making It Look Bad
A photo that arrives as a huge email attachment is slow to send and slow to open, and it is usually no sharper on screen than a version a fraction of the size. Compression closes that gap by removing data the eye is unlikely to miss, provided you remove the right data.
Image Compressor makes the file smaller and shows you the saving before you download it. This guide explains why compressed photos sometimes look worse, and how to avoid the usual mistakes.
Quick answer
Resize the picture to the dimensions it will actually be displayed at, then compress at a moderate quality. Photographs survive this well because they contain soft detail. Screenshots, text, and images with hard edges show damage sooner, so judge the result at full size rather than in a thumbnail.
Why compression damages some images more than others
Most photo compression is lossy: the encoder discards detail, especially where colours change quickly. In a landscape or a portrait, that detail sits in foliage, skin texture, and clouds, where the eye is forgiving. In a screenshot of a document, the same process produces blocky halos around every letter.
Saving an already compressed image again compounds the loss. Each pass re-encodes the artefacts from the previous one, so a photo that has been through several editors can look muddy even at a high quality setting. Work from the original wherever possible, and save once at the end.
Resize before you compress
A camera photo can be several thousand pixels wide. If it will appear in an email at a few hundred pixels, most of those pixels are wasted, and no compressor can recover the space they take. Set the long edge to roughly the size it will be shown at, then compress the smaller file.
For social posts, the required shape matters as much as the size, and the Social Image Resize tool covers the common formats. Cropping to the right ratio first means you are not paying for pixels that will be trimmed away later.
Choosing a format and quality
JPEG remains the safest choice for photographs. PNG is better for screenshots, logos, and anything with transparency, but it is usually much larger for photos. WebP can be smaller again, though some older software and upload forms still refuse it; if you need to convert, see WebP to JPG or PNG.
On the quality slider, the middle of the range is usually enough for photographs. Going higher mostly preserves detail that will not survive being displayed at a smaller size. Going much lower starts to produce visible blocking in flat areas such as skies.
Check the result at full size
Open the compressed file at 100% and look where artefacts appear first: the edge of a face against a background, thin branches, small text, and smooth gradients. Compare it with the original side by side. If the difference is only visible when you look for it, the file is small enough and good enough.
If it is not, raise the quality slightly or reduce the dimensions further. Compression is a trade, not a switch, and the right setting depends on where the image will be seen.
When you are ready, run the file through Image Compressor, check the preview, and download the version that looks right at the size you need.
Common questions
Should I resize an image before compressing it?
Yes. Set the long edge to roughly the size the picture will be displayed at, then compress the smaller file. Extra pixels cannot be recovered by compression, so they only add weight. For social posts, crop to the required shape first so you are not paying for pixels that will be trimmed away.
Why does a compressed screenshot look worse than a compressed photo?
Lossy compression discards detail, especially where colours change quickly. In a landscape or portrait that detail sits in foliage, skin texture, and clouds, where the eye is forgiving. In a screenshot of a document, the same process produces blocky halos around every letter. Hard edges show damage sooner, so judge the result at full size.
What quality setting should I use when compressing a photo?
The middle of the quality range is usually enough for photographs. Higher settings mostly preserve detail that will not survive being displayed at a smaller size, while much lower settings start to produce visible blocking in flat areas such as skies. Check the file at 100% and raise the quality slightly or reduce the dimensions if needed.