Thread:Project:Support desk/uploading file getting error "Error creating thumbnail: /bin/bash: /usr/bin/convert: Is a directory"/reply (4)

"convert" is not a directory, it is a command provided by ImageMagick. The $wgImageMagickConvertCommand should give the full path of the convert command, and it is usually installed in /usr/bin, so that is why it is usually set to "/usr/bin/convert".

Remove the /usr/bin/convert directory you made and install ImageMagick. The link Ciencia provided tells you where to go for that, or look for it in whatever package manager your system is using.

jpegs are being converted by something else, perhaps GD as part of your PHP install, as that same linked page explains.