.

Apparently, you can change your code to rescale icons as needed.

https://mods.factorio.com/mod/MoreScience/discussion/5e3b8cd1da6d8f000b09639e

I might do it myself.

Its also creating issues with other mods.

https://imgur.com/lCUH0a2

I'll look through the code to see if it can be fixed.
I didn't make the original mod so I don't really know the code, and i'm very inexperienced with lua, though, so i don't know if i can fix it.

If diesel is not found, the code is going through all of the fluids in the game and adding them as potential fuels, even though it shouldn't need to do that. If I try to make it so that it only does light and heavy oil, it might cause problems if you try to put the wrong fluid in to the locomotive.

Now i've fixed that issue, but it crashes if you try to put water in.

Well, the problem is that it requires 64x64 on all fluid icons, whether it can use it or not. You should be able to simply rescale them to 64x64 instead of requiring the source to be so.

The thing is is that it's just simpler to have it only care about light and heavy oil, and fix the original problem, than to put in if statements to resize everything

So only put fuel fluids in, got it!

Once this is updated, anyway...

For some reason the mod still tries to use the fluid prototypes from other mods, even though they aren't diesel, and even if I comment the diesel it still tries to use them. The new update does fix the original issue, though.