Convert rm4 to dds Online: rm42dds
You can use Tom's Editor to easily convert images from
Rambrandt .RM4 to Direct Show Surface
Tom's Editor is a free, online image manipulation and converter program.
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Rambrandt is an image format with extension RM4.
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.