Under RISC OS 3.6 and later, JPEG files are supported natively by the operating system. This is done through extensions to the SpriteExtend module, which has been given extra code to deal with these files. RISC OS 3.5 users can soft-load this extension and give partial support for these files too.
Unfortunately, only Risc PC owners can use such versions of SpriteExtend as the module creates a Dynamic Area to use as workspace whilst plotting JPEGs. Dynamic Areas are not available on pre-Risc PC machines. The SpriteExtend's JPEG code is remarkably fast given how difficult JPEGs are to display, but there are some limitations in the type of JPEGs that are supported - it does support the common formats, though. Acorn's ChangeFSI application can always be used as a fallback if SpriteExtend can't display the picture, albeit a comparatively slow alternative.
Acorn have released an unsupported version of SpriteExtend for RISC OS 3.5 users, which appears to work with SwiftJPEG well. This will not give !Draw, !Paint and so-on the ability to load JPEGs! A copy of the module is available on Acorn's FTP site; to download it, click on the following link:
Versions 0.99 and later of SpriteExtend are 'JPEG-aware'.