Uploading an image file via Store Commander's interface can generate a HTTP error and display a yellow triangle in the upload window:
This happens when write permissions are not high enough on your FTP /img/p directory/.
Use the recursion option when modifiying permissions on this directory so that they are applied to all sub-folders.
Please also check (with your hosting provider if need be) that newly created folders and files inherit the same permissions as the parent folder.
indeed, when adding an image to a product, a folder is automatically created (containing the image file) in /img/p/, for instance /img/p/1/3/4/5. And if permissions are not sufficient for an image to be added then the server will display an ERR (103) in Store Commander.
It is therefore necessary for newly created files and folders to inherit permissions of the parent folder /img/p/.