Convert jp2k to gif Online: jp2k2gif

You can use Tom's Editor to easily convert images from
JPEG 2000 .JP2K to CompuServe Graphics Interchange Format .GIF.
Tom's Editor is a free, online image manipulation and converter program.

Go to Tom's Editor

JP2K

JPEG 2000 is an image format with extension JP2K.

GIF

GIF images were created by Compuserve. They can used no more than 256 colors and a single color transparenty (no Alpha channel). Today are rare since they offer low quality and huge filesizes. GIF animations are still in use.