Two types of graphic formats on the horizon look promising : JPEG2000 and vector-based graphics.
The new JPEG2000 format is designed to be a superior replacement for the popular JPEG format. The JPEG2000 format uses wavelet technology to achieve higher compression ratios with radically reduced artifacts. The JPEG2000 format can compress images to 100:1 ratios or higher with much less image degradation than JPEGs. JPEG2000 also has a lossless compression option that typically achieves 3:1 to 4:1 compression. The JPEG2000 specification has been approved, but we won't see widespread use of this image format until browsers embed a JPEG2000 decompressor within their code.
There are too many tools to list them all here. The following list includes only tools with PNG support. Most of them support GIF and JPEG as well.
The most popular of these are listed here: