Header Image Not Showing – Very Dark

I am working with the Astrid theme. I uploaded a new pic for the header and it does not show correctly. I can see the pic but it is very dark – almost not visible. I have tried changing the file size but it has not changed anything.

Also, is this the place to post such questions? I tried to look for the “view support forum” link for the Astrid theme but could not find it.

Regards,