Storage optimization with compressed file format?

[lim185]

Currently we store images as 16-bit depth tiff files. Saving the images in lossless compressed format (e.g. png) instead of the uncompressed tiff format can save considerable amount of storage. A test image from alpha prime shows raw / compressed file size ratio of 1.79. However, the tradeoff is the runtime; in the above test the runtime was 3.74 times slower with the compressed format (because the code has to perform decompression on the fly for every image).

Depending on what we decide to prioritize, we can either keep the current format or switch. It will not affect other resources (e.g. memory).