The only software we know of, that can convert .spf pictures (Still Picture Interchange Format) to any other format (including PNG), would be Adobe Photoshop that can open, thus export, SPF format just fine. But perhaps there may exist other graphics programs capable of the very same thing.
Convert Still Picture Interchange File Format to Portable Network Graphic.
We found 2 software records in the database related to .spf to .png file format conversion.
Microsoft Windows software - convert spf to png on Windows
One of the best bitmap graphic editing program
Convert from spf file format
|Yes, Adobe Photoshop supports png file conversion as a target file type.||Yes||Yes||png editor||Yes||Yes||Yes||No|
The tables with software actions are a good pointer for what a certain program does with various file types and often may give users a good hint how to perform certain file conversion, for example the above-mentioned spf to png. However, it is not perfect and sometimes can show results which are not really usable because of how certain programs work with files and the possible conversion is thus actually not possible at all.
Apple macOS / Mac OS X software - convert spf to png on OS X
Mac version of popular digital image editor