Hello,
I made a texture in .jpg for my map. I used it in Radiant, was successfully loaded. Then i opened the map and saw, that texture is not loading- i can only see an orange-black “crossword”.
Dunno what i’m doing wrong. Friend told it may be caused by wrong working shader in someones map i downloaded 
Please, help me 
Just be sure your pic has one of these formats: 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024
For example: 2 x 2 or 128 x 128
It can be 64 x 128 too
oooooooooooooooor, if your textures are black/orange/white or any other color their not suppose to be, follow these directions!!
1:Hit the Textures tab.
2:Hit Flush and Flush and Reload shaders.
3:Either it should work then, or just restart radiant.
:moo:
The error is most likley spelling or syntax error if you have a shader for it. And as long as the texture has the dimensions that are a power of 2 like Snake said.
Also just a note, in your shader make sure you dont use .jpg as an extension, eaven though thats what the texture is, the shader should always have .tga as the extension of a texture.