How do I remove a ColorSync profile from a JPEG image from Terminal in El Capitan?
Use sips (scriptable image processing system) to remove an ICC color profile from an image file in El Capitan. sips does a ton of other stuff as well.

To remove the ColorSync ICC profile from an image:

sips -d profile --deleteColorManagementProperties &lt;imagefile&gt;


Example:

MyFILE="${HOME}/Pictures/RemoveMyColorSyncProfile.jpg";
sips -d profile --deleteColorManagementProperties "${MyFILE}";


It appears to support the following image types, but I'm basing this on the format image property key (see Options in the man page):


jpeg
tiff
png
gif
jp2
pict
bmp
qtif
psd
sgi
tga


See the man page for more info, or use sips -h for help to stdout.