I have it solves in another way for me.
And it works. I have the same problem in several project.
All pictures above 1500px width not works with the upload. All below was ok.
I have updated the php.ini file in the root of the server, and the wp-admin folder also (placed 2 times).
Update the server on php 5.5 and it works again.
php.ini
upload_max_filesize = 64M
post_max_size = 64M
max_execution_time = 300
But I have also read, that this is an Problem with 1and1 Servers.
