From GameBrew - a wiki dedicated to Video Game Homebrew.
A photo viewer designed for R4 ispecially, which you can use it to browse image and cartoon.
Use the img2ipk to convert the JPG, PNG, and BMP files to be IPK file (the sample is available in the directory IPK: example.ipk).
Copy the IPK file and the imgview06_R4TF_M3Simply-R4DS (MicroSD Card).nds to the CF card.
Run the NDS program on the R4 interface.