When you delete something off of an sd card do the corpse files stay on the sd card?

Answer 1

When you delete something from electronic media - whether that's a CD, DVD or solid state drive (SD card etc) the original data stays on the medium until the space it occupies is needed by new data.

Deleting something simply removes the file's 'reference data' from the directory on the media. Removing the reference data simply means a computer no longer recognises the file - but the data from the file stays unto the space is needed.

The only 'sure-fire' way to delete data is to do a 'low-level' format of the media - which involves the computer over-writing the whole media with zeros.