This is a big job!
Currently the new GL2ES2Pipeline supports these image formats, and the switch case can be easily put into the JoglPipeline
However the real issue is that the file loading code for these is a very large amount of code - 9 classes in java3d-core package and 30+ in external files, some of which is third party code and it's license status is unknown
So some thought will need to go into how to move forward on this.
If this enhancement is done this bug must also be done
Bug 1332 - Texture Mip Map count checking incorrect