A question on `METADATA_BLOCK_PICTURE` tag

My Leaders, Teachers and Seniors,
I continue to use the same debian 12.6.0 lxqt and audacity.
An m4a file downloaded from the internet had a picture attached, which was displayed both by smplayer and mpv media player.

I briefly checked the file in audacity. It had the tag, METADATA_BLOCK_PICTURE included, and the pic code in base64 beside the said tag.

However, when I tried to insert my own pic with the code attached herewith to display the said pic, I couldn’t have it displayed by the said two audio-video players.

Do I need to remove some parts from the base64 file that I created from the image file? The said files are as follows:
personalmsg.txt (9.3 KB)
personalmsg|451x104

I briefly checked all the recommendations provided by Your topic is similar to… , but didn’t find any insight on the aspect.

Am I missing/overlooking something important?

Audacity cannot add artwork to audio metadata. Need a tag editor for that …

Yes, the hint, though too broad to select a particular package, worked. All the relevant 3 found: easytag, kid3 and puddletag – I could easily be missing others – ‘search by default’ the Music directory for all audio files in the said directory, which is unnecessary and undesirable as there aren’t files there.

When led to the particular file through the in-built file browser, it sorts and displays all the audio files therein. This too is undesirable.

Didn’t find DeaDBeeF, Exaile aren’t available. Didn’t yet check Quod Libet or Rhythmbox.

A lighter program, with an option only to open a desirable file and add the metadata tag and image file would have been desirable.

However, there is a shortcut. I could have a separate directory for files to be edited by easytag as a temporary means.

I hope that in the coming days I would be able to find one such.

But thank you for the initial input, Mr. Trebor. Much appreciated.

I’m a Window guy, but…

Most audio player applications can edit metadata so you might want to check that with whatever player you are using.

MP3Tag is the best metadata editor I know of. I don’t know if there is a version for debian, but Google could help with that.

Ok. Thank you. I will check.
I use smplayer and mpv player. Sometimes, audacious. Whatever available with the ISO.