Samsung could be releasing a Galaxy S IV Mini in May, shortly after the Galaxy S IV itself, if rumors are to be believed. The smaller version of the expected Galaxy S IV is said to be released at some point in May, and though light on details relating to specifications, it should follow a similar pattern to the Mini variant of the Galaxy S III.
Sources of SamMobile claim that Project J Active, codenamed Fortius and identified as the Galaxy S IV, would be followed by the Project J Mini, codenamed Serrano. Accessories for the Project J Mini, such as a clear cover, flip cover, and a protective cover, apparently need to be done by Week 21, which would be between May 20th and May 26th.
The Galaxy S III Mini turned out to be a neutered version of the Galaxy S III, offering the styling and a number of the features found in its bigger stablemate, though with lower specifications and a 4-inch form. If the Mini for the Galaxy S IV is a similar concept to the Galaxy S III Mini, it will likely have a slower processor, lower-resolution camera, and a much smaller screen, among other features.