Convert ithmb to dds Online: ithmb2dds
You can use Tom's Editor to easily convert images from
.ITHMB to Direct Show Surface
Tom's Editor is a free, online image manipulation and converter program.
Go to Tom's Editor
ITHMB are thumbnails used by various Apple devices. At first these images were used by iPhods but now can be found on iPhones and iPads.
DDS are files invented by Microsoft to be used in games, mostly as textures. Images can be compressed to save space but the compression methods defined by DDS are all very fast in terms of coding and decoding.