No, I'm not referring to the physical size of the image....I'm talking about the
file size of the image, the amount of memory it takes to reproduce the image.
If you take a look at most images that relate to the model's the game uses (found in the "Textures/TNormal/tex" folder) you'll see the largest size for most material images are 1024x1024. Some are smaller, but only a handful are larger. I just made a guess at choosing 1024x1024 for the materials image used for the propellers. In the following image, the S3D prop model UV Map preview shows the model, but it doesn't state the size of the model.
To do it right, I should have "Exported" the model into something like Blender to see just how large the model truly is....then made my red colored image to match the size of the model. 1024x1024 was just a guess. Making a material image smaller in physical size then 1024x1024
COULD have made the color
not show on the prop model at all.
No, I'm referring to the image size that requires a certain amount of memory to be used to reproduce the image. A modder needs to be careful what he adds to the image that may not be needed. The more you add, the larger the memory you'll need to reproduce the same sized image.
In a .dds image you can add MipMaps, Alpha Channels, change the color pallet....all requiring extra memory to show the image. If you don't need the extras....don't use them. Keep the materials memory image as small as possible.
In the following picture, the nVidia Plug-In is opened in PhotoShop for saving a .dds image. The color pallet is 4 bpp, with no Alpha Channel, but with MipMaps enabled. Notice the physical size of the image (in the lower left corner) is 1024x1024:
This DXT1 .dds format will produce an image of about 683Kb in file size. Without the MipMaps generated, the same image is about 513Kb in size.
If you increase the color pallet, add an Alpha Channel, yet don't generate the MipMaps, the size of the DXT5 file will be about 1,025Kb (still producing a 1024x1024 image). Adding the MipMaps will boost the memory requirement to 1,366Kb.
As the following image shows, a 1024x1024 .bmp image is 3,000Kb in file size. The various 1024x1024 .dds formated images all have different memory file size requirements.
What I'm saying is a modder should know which material image works best for the particular model its used for....with the expectation of using as small amount of memory as possible. Keeping in mind that a handful of images isn't going to hurt preformance too much, yet having many large file size images not paired to the task needed can easily cause slow downs in game play.