That's really unfortunate.
But if that's the case why does base starsector start perfectly fine. I don't think all of it's images are in caps.
I renamed uin.png to UIN.ong and got a new error:
Spoiler
26921 [Thread-5] DEBUG com.fs.graphics.TextureLoader - Loading [graphics/portraits/portrait_mercenary02.png] as texture with id [graphics/portraits/portrait_mercenary02.png]
26938 [Thread-5] DEBUG com.fs.graphics.TextureLoader - Loaded 167.65 MB of texture data so far
26938 [Thread-5] INFO com.fs.graphics.TextureLoader - Cleaned buffer for texture graphics/portraits/portrait_mercenary02.png (using cast)
26938 [Thread-5] DEBUG com.fs.graphics.TextureLoader - Loading [graphics/portraits/portrait_mercenary03.png] as texture with id [graphics/portraits/portrait_mercenary03.png]
26954 [Thread-5] DEBUG com.fs.graphics.TextureLoader - Loaded 167.73 MB of texture data so far
26954 [Thread-5] INFO com.fs.graphics.TextureLoader - Cleaned buffer for texture graphics/portraits/portrait_mercenary03.png (using cast)
26955 [Thread-5] DEBUG com.fs.graphics.TextureLoader - Loading [graphics/factions/uin.png] as texture with id [graphics/factions/uin.png]
_xgeWireToEvent: Unknown extension 148, this should never happen.
_xgeWireToEvent: Unknown extension 148, this should never happen.
26980 [Thread-5] ERROR com.fs.starfarer.combat.D - java.lang.RuntimeException: Error loading [graphics/factions/uin.png] resource, not found in [/home/jane/Docs/games/starsector/./mods/ironclads2,../starfarer.res/res,CLASSPATH]
java.lang.RuntimeException: Error loading [graphics/factions/uin.png] resource, not found in [/home/jane/Docs/games/starsector/./mods/ironclads2,../starfarer.res/res,CLASSPATH]
at com.fs.util.C.Ó00000(Unknown Source)
at com.fs.util.C.Ô00000(Unknown Source)
at com.fs.graphics.TextureLoader.Ò00000(Unknown Source)
at com.fs.graphics.TextureLoader.o00000(Unknown Source)
at com.fs.graphics.TextureLoader.o00000(Unknown Source)
at com.fs.graphics.TextureLoader.o00000(Unknown Source)
at com.fs.graphics.OooOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO.o00000(Unknown Source)
at com.fs.starfarer.loading.G.super(Unknown Source)
at com.fs.A.A.Ò00000(Unknown Source)
at com.fs.starfarer.combat.D.o00000(Unknown Source)
at com.fs.starfarer.StarfarerLauncher$2.run(Unknown Source)
at java.lang.Thread.run(Thread.java:745)
So I just copied uin.png and renamed the new one to UIN.png and it started perfectly