This, and use PNG or DDS
The power of two has nothing to do with the image quality. It has more to do with the way video cards do calculations on your texture. Older video cards had problems handling textures that were not sized by factors of two. Newer video cards don’t have that problem but for compatibility issues it is always recommended to always size your textures by factor of two.
.TIF commonly uses JPEG compression (if any), and JPEG compression is not meant to be used on 3D.
I Created a texture that is 4096X4096 for my 3d object. this has made rendering a bit slow.I would like to reduce my texture size down to 1024X1024. Is there a way in blender to reduce the texture size with out having to re create a new image in blender then go back to Photoshop to create a texture that Fits the new UVMap?