PSP theming has sure come along way, and we can thank ZiNgA BuRgA for providing the necessary customization tools allowing various aspects of the XMB to be personalized. RCO Editor enables easy manipulation of localized resources (*.rco files) — icons, sounds, text, etc… Basically anything & everything that makes the XMB what it is.

Changes in 1.15c:

• Fixed another bug in GIM conversion routine

Changes in 1.15b:

• Fixed a bug in the decompression and GIM conversion routine

Changes in 1.15:

• Rewrote GIM < -> BMP conversion routine
• Dimension restrictions removed, as well as the “visible dimension” nonsense (RCO Editor automatically fixes that)
• osk_utility.rco icons no longer cause crashes
• Support for creating 4 bit and 32 bit GIMs (previously, only 8 bit supported) - effectively removing the 256 colour restriction
• You can now use ICO, PNG and GIF files as inputs, in addition to 4 bit BMPs
• Other minor changes and bug fixes
• Added option to disable compressing resources - this is for some 3.7x RCOs not working properly with compression enabled

Download: RCO Editor v1.15c

- source: endlessparadigm

p.s. Apologies for the downtime