Image Compression Tools: Shrinking Images Without Visible Loss
Lossy versus lossless, resize before compress, pick the right format. Here is how I compress images for the web. Image compression is where most of the bytes on a web page live, and it is where the easiest performance wins are. An uncompressed hero image can be five megabytes. The same image, compressed well, is three hundred kilobytes and visually identical. Online image compression tools make this optimization accessible without desktop software. Here is how I use them and what I have learned about getting the best results. Lossy Versus Lossless: Choose Deliberately Compression comes in two types. Lossless compression reduces file size without discarding any image data; the decompressed image is pixel-identical to the original. Lossy compression discards data that the human eye is less sensitive to, producing a smaller file at the cost of quality. The choice depends on the use case. For photographs on the web, I use lossy compression, because the quality loss is barely visible and the size savings are large. For images that must be pixel-perfect, like screenshots of text or technical diagrams, I use lossless compression, because lossy artifacts on text and sharp lines are immediately visible. More tutorials are on the KitCraft Blog.