is "Impossible to detect message." 100% true?

[andreacfromtheapp]

hi,

I haven't used stegano-lsb in a long while and today I wanted to check my "documents". I have a mnemonic to remember the list, and I am going through all of them. Some of the successfully, some other not. The latter return:

stegano-lsb reveal -i yadayada.png
Impossible to detect message.

To be honest I can't remember if the ones that fail have been cleaned up in the past and their secrets ditched as no longer needed. (e.g: I don't have use to save a certain backup recovery key since I don't use the software anymore).

My question is:

• if reveal return the above message, it does mean 100% that there is nothing hidden in that image?

If not, I tried using -o yadayada.extension but it's just the same.

Please and thank you