How do I get album art to sansa when using FLAC

Was having trouble myself with a SanDisk Clip Sport here in 2015. Turns out the particular format of JPEG was the problem. Opened it back up in GIMP and expanded the ‘Advanced Options’ pref area and disabled everything extraneous (‘Optimize’, & ‘Progressive’), resaved the file as the same ‘folder.jpg’ and it worked just fine. It’s understandable, I guess, that such a small device might only support the basest type of JPEG.