Core-Theme on I-Phone/I-Pad

Hi out there,
I am really new in the WordPress world, and I have a question – I bought the core theme for photographers, and on computers everything works fine; but then when it goes to mobile-devices, problems start, especially at the I-Phone (probably at the I-Pad too):

In my theme-settings I have the possibility:”Enable/disable main menu and footer auto hiding”. So on the hp the sidebars disappear after a few seconds not moving the cursor, and pictures are there full screen. After moving the cursor, the sidebars appear again and you can use the menu then.
I really like that, looks nice i think, but yesterday a friend told me, that if he visits my hp via I-phone, the sidebars disappear, but they don t come back if you touch the screen, so can t ever visit the galleries and stuff. Does anybody have an idea, how I could keep that “Enable/disable main menu and footer auto hiding “-possibility, because I disabled it for now.

And one other thing: the thumbnails are big as I like them – but on the mobile devices they are cut in the half (because too big for display) – any possibility that they are shown smaller on mobiles, but big as now on computers?

my page is http://www.gregorbuchhaus.com

Thanks for reading patience, and would be great to get some support (and please mention that I am a web-page-rookie)

Cheers,
Gregor