Fast on-the-fly image decompression

Question

I need to work with a good amount of 4-bit images. However, it's got to be for J2ME devices, which means great lack of memory. So, could you propose a compression algorithm that could decompress on the fly relatively fast and still have some reasonable degree of compression?

Answer 1

It depends on the nature of your images. Simple run length encoding (RLE) might be enough and it's trivial to implement and very fast.

Answer 2

For most practical uses, I would use an existing software compression package rather than implementing one myself.

Try imagemagick covnert, it is fast, flexible and open source.