First you need. ResHacker:
[You must be registered and logged in to see this link.]Next install and open.
Click File on the top left corner, click Open.
Find your GFX Endless-Online file.
When u open GFX folder there will be nothing there.
Under File Name at the bottom there will be Files Of Type.
Across from that there will be an Arrow.
Click the arrow, click All Files.
Open one fo the GFX files (13 Male armour).
Once you show all Click the little + on BitMaps.
After that click View on top,
Click Expand Tree.
Rightclick one of the BitMap Files With the "Green Flower" icon.
Click Save All Resources. Save them somewhere.
Go tot the Folder where you have saved your Files (preferably Desktop, Or somewhere for easy access.), Open the folder.
One in there Rigth click what ever image you want to change and click Edit.
Once in Paint Zoom to Maximum.
Edit your file and save.
Hope you understood this. If anyone wants me to I will help with making Editing easier, and more things.
Thanks for reading.