Attached are 3 .SPS files that 'identify' as Spectrum 512S files but do not convert properly with recoil2png. It's quite possible these are not Spectrum 512S files at all
I don't remember where I got them and 2 of the files are exactly 8192 bytes long which seems suspicious. I know the 'magic' for SPS files is pretty weak, so if these are not Spectrum 512S files at all, just close and sorry for wasting time.
These files come from this CD: https://archive.org/details/atari-gemini
They are in a 'specpics' folder.
Found 3 more files that don't convert well from the same source CD. 1 SPS and 2 SPC.
This CD is in my collection as physical copy and ISO. Found all 6 images on the ISO from both archives. None of them load correctly. Testing files with Atari ST emulator. Back in the day this CD was notorious for bad files.
Thanks, Lonny!