error when uploading avatar

[LLLRH]

When I am uploading avatar, I got message " spawn convert ENOPEN";
when I check it with "./nodebb log" the error message is shown:

• 23/5 14:50 [3699] - error: /api/user/root/uploadpicture
  Error: spawn convert ENOENT
  at exports._errnoException (util.js:746:11)
  at Process.ChildProcess._handle.onexit (child_process.js:1053:32)
  at child_process.js:1144:20
  at process._tickCallback (node.js:355:11)*

any suggestion?
BTW, the nodebb version is 0.70 and installed on a Mac , the "/public/uploads" path permission is ok for write

[Firelad]

Wrong category.

And it seems it means the file size is too huge, that NodeBB (probably) can't read and gives this error.

[LLLRH]

the size is less 10K