Image compression comes in two main types: lossy and lossless.

Lossy compression reduces file size by permanently removing some data. This results in smaller files but some quality loss. JPEG uses lossy compression and is ideal for photographs.

Lossy compression reduces file size by removing data

Lossless compression reduces file size without losing any data. PNG uses lossless compression and is perfect for graphics, logos, and images with text.

When choosing compression:
- Use lossy for photos where small quality loss is acceptable
- Use lossless for graphics, logos, and images with sharp edges
- Consider the end use: web display vs print

Tools like CompressorPic allow you to choose between different compression levels to find the perfect balance between file size and quality.