texture mapping X1 R5 G5 B5 bitmaps

I dont know how to texture map a bitmap which is saved like this in Photoshop. For 24 bpp bitmaps i pass GL_RGB to gluBuild2DMipMaps but when I pass GL_RGB for a X1 R5 G5 B5 image it isnt dispalyed correctly. Please help.

that looks like a DXT1 dds format. theres clearly 1 bit of x, or transparent alpha, so its not strictly a rgb image. load the dds, and either convert it to rgb manually, or use one of gl’s compressed format type extensions (GL_COMPRESSED_RGBA_S3TC_DXT1_EXT).