I’m trying to create dice in Blender. I’m going to put different pictures on each cubes face. It seems it is not so easy. Have tried to use the UV editor but without success. Is it possible to do it?
Yes in the uv editor and also with only materials and textures . just assign a material to each face a different color to keep track. then in textures use a image or movie and mapping a cube. I think that should do it for ya
I’m not a pro with this either, but you could also do it with a single material and texture 
here’s how I’d do it;
(aaah damn, i wanted to add some images to this to make a few things more clear, but it doesn’t let me add more than three pictures 
ah well, I merged them together and added them below the following text.
#1 Get your basic cube
#2 Assign a Material to it and to this Material a Texture.
#3 as Texture Type select ‘Image or Movie’
#4 Generate a Image that you want to use for the Texture
#5 in the Mapping options select UV
your options now should look somewhat like in the picture (1)
#6 With your cube, go to Edit mode, and select the Edges like shown in the picture (2)
#7 Mark them as seams (Strg+E is the shortcut for the edge tools)
this is a preparation for the unwrapping, so the faces are unwrapped like in the picture (3)
#8 in the image editor, select the texture you want.
in edit mode select all faces of your cube and press ‘u’ to unwrap.
just use the standard ‘unwrap’ method (top one). the seams will make sure it’s properly unwrapped.
it should look like shown now.
#9 You can take this UV Data now and export it as an image
(UVs -> Export UV Layout)
#10 now you can use an image manipulation program of your choice to paint the individual Faces as you want
mine - made with the gimp - looks like this; Image(4)
#11 in the texture options for your cube unlink the created blank image, and load the modified version with the actual painted faces.
(you may have to unwrap UVs for this image again)
#12 Render. There you go
Edit: fixed some spelling and grammar mistakes.
English is not my native language, so sorry for any other mistakes I didn’t notice or parts that don’t make sense 
Edit2: And if you keep your texture nice and clean you won’t have those ugly dark edges on your finished cube, that I have -.- ah well, I think the process in itself was made clear