My sysadmin updated our server and now I am getting these errors. I have read others posts regarding similar errors and cannot figure out what may be causing my issue. Any ideas?

prince: http://172.21.110.31/attachment/78602/2015_03_09_20_52_098.png: warning: Unknown image MIME type: text/html
prince: http://172.21.110.31/attachment/78602/2015_03_09_20_52_098.png: warning: Unknown image format
prince: http://172.21.110.31/attachment/83715/2016_01_15_00_05_271.png: warning: Unknown image MIME type: text/html
prince: http://172.21.110.31/attachment/83715/2016_01_15_00_05_271.png: warning: Unknown image format

I also see this in the logs which is not there in my working server:
yes(resource_type("image/png", [], image(png), no)).

The log from my working server has this:
yes(resource_type("image/png", ["charset" - "iso-8859-1"], image(png), yes(iso_8859_1)))

Could you attach or email me (mikeday@yeslogic.com) the full debug log output?

This issue occurs when the server requires additional authentication to access the image, and redirects to a HTML login page.