Sometimes when you create a model in Blender you will find that exporting it, compiling it will result in a beautiful Pink Plane like this
How to solve this fast without needing to go into a graphics package to make sure your textures are divisible by 4 (this is a game engine thing needed for optimisation), is Open the Image Editor in Blender, select the image that you need to resize and click Image > Resize
Once you are happy with the size, don’t forget to go Image > Save
Hope it helps