General Support: Adding things like upload_max_filesize in .hatccess breaks the gallery

This is not a dedicated server so I cannot really reboot servers as I please. I am trying to fix the .htaccess so I can upload larger / more photos at the same time via the "Import" function of the backend administration.

If I could make the server refresh the php.ini values, I would add something like this:

upload_max_filesize = 25M
post_max_size = 750M
max_execution_time = 900
memory_limit = 750M

Unfortunately similar syntax or even "php_value upload_max_filesize 25M" does not work. It seems as soon as I put one mention of this attributes, the gallery immediately breaks. By "breaking", I mean that the photos no longer show up... it's like all the images and style disappears.

Any idea what I am doing wrong?

Thank you