First off, you will need an image editing application, MS Paint is really not ideal, if you want a free application, your best bet is GIMP which is open source. In addition, you will need a copy of GoFSH, "the Swiss Army Knife" of SC4 texturing: Since I have textures all over the place, I've put together a small repository (attached). Using GoFSH, a lot of the work can be automated. Don't mess with the directory structure of the texture repository, extract it as-is or you'll quickly run into problems. Because I'm responding to a user request from @Handyman, I'll focus briefly on how to remove the manhole/grilles on these textures. But you could edit these in many different ways, depending on your requirements. Using the supplied script, select the "Run Script" option in GoFSH, it will re-compile a ready-to-use override DAT, with minimal effort. You simply need to edit the textures beforehand... in fact, it's easier than that for about 90% of them, thanks to something called Definition Alphas. In the example above, it shows a "texture pair". The imagine on the left is the SC4 Texture (Straight Road FLUP), the image on the right is the Definition Alpha. It's easy to identify them, the first ends in -C0.bmp, the latter in -D0.bmp.  See the small white holes on the edges (circled in red - far right)?  The white parts are ignored (i.e. it doesn't modify that part of the texture), which you need to change. Just edit the D0 texture and fill that gap with the correct colour, Green for Sidewalk or Cyan for grass. When you run the script afterwards, it will replace the grates with sidewalk instead, without any further effort. Just be careful to get the right shade, these are based on RGB values: Green = 0,255,0 Cyan   = 0,255,255 This might sound more complex than it is... but you just need to use the Eyedropper tool (or equivalent) to pick up the colour from the existing image. This works when the gill covers the sidewalk/grass area. But for some textures where the gill is part of the texture itself, you'll need to edit the actual texture to remove it. Is essence, find a texture without the grill in that spot, place that over the original as a new layer, remove any excess parts you don't need on this layer, and save the new file. NAM FLUPs Repository.zip