Pensoffsky has updated his PeP Viewer to version 0.6.5. PeP Viewer, or Pens Enhanced Picture Viewer, is an application designed for reading manga on your PSP. This program is very nicely made and has many features, including: .bmp, .jpeg, .png image support, adjustable scroll speed via both the analog stick and d-pad, a bookmark system and a music player for .ogg music files. Here is the changelog for the latest version:

bmp, jpeg, png, ... support
scroll, rotate, resize pictures
adjustable scroll speed for the analog stick & digi-pad
dynamic scrolling with the analog stick
bookmark system
security questions when deleting or overwriting a bookmark
mp3player (basic)
adjustable CPU speed
show image on top/center/bottom and left/center/right option
adjustable X & Y offset
strange GUI :)