A photo straight off a modern phone camera is often 4000 pixels wide and several megabytes large. Your website is probably going to display it at 800 pixels wide. Uploading it as-is means every visitor downloads five times more image data than they'll ever actually see — and that adds up fast across a whole page.
Resize first, then compress
Resizing an image down to the dimensions it will actually be displayed at removes far more excess data than compression alone ever can. Compressing an oversized image just produces a smaller version of something that was still too big to begin with. Get the dimensions right first, and compression only has to do the smaller job of fine-tuning quality.
How much does compression really save
Most photos can drop to somewhere between 60% and 80% quality with a difference that's barely noticeable to the eye, while cutting file size substantially. Push much lower than that and you'll start to see visible artifacts — blotchy patches of color, especially around sharp edges or text within the image.
A simple three-step workflow
- Resize the image to the maximum width your website or platform actually needs.
- Compress it, then compare the result against the original at full zoom.
- Convert to JPG if you're starting from a heavier format like PNG or HEIC that isn't necessary for an ordinary photo.
Which format should you actually use
- JPG — best for photos and anything with lots of color detail and no transparency.
- PNG — best for logos, screenshots, and graphics that need transparency or sharp, flat colors.
- HEIC (the default format on many iPhones) isn't reliably supported by every website or platform — convert it to JPG first for universal compatibility.
Not sure what width to resize to? Check your website theme or platform's recommended image dimensions. Uploading anything larger just gets scaled down by the browser anyway — wasting bandwidth for every single visitor who loads the page.
One image at a time, on purpose
These tools process one image at a time by design. That keeps the before-and-after preview accurate and lets you judge quality properly, rather than applying one guessed setting across a whole batch and hoping every photo turned out fine.
A little bit of resizing before you compress — and picking the right format — usually does more for page speed than any other single change you can make to your images.