I have an image texture material on a mesh already in blender cycles 2.75... I was wondering how to change the material with keyframes so it changes to different pictures in the animation... I tried image sequence, but that doesn't seem to be what I am trying to achieve, neither does pressing "i" on the image source in the materials tab, it just says that the name property can not be animated ... Could someone help?
Check the UVs box in the AnimAll panel. Go to the frame you like and place the UV island in UV Editor wherever you like (enable the magnet icon and set its type to Increment to move it precisely). Now press Insert button as pictured below.
Here are my other answers that uses an Animall adon, that may help you:
To dissolve one image into another, connect the different image textures to a color mix node, before the shader node. By animating the Mix Factor you can control the how the images change.
Cascading this node setup might work for a few images.
But if you have many images, you might want to turn them into an image sequence (just renaming them with the same name and progressive numbers will work). Then load the image sequence as a texture.
If what you want to do is have the image change with every frame of your scene use the default options and use autorefresh.
If you want to manually set the duration of each image. Set the number of frames and start frame to 1 and animate the offset value.
Note that by doing this the images will change from one frame to the next but will not dissolve gradually.