Here is a way to make sure a folder not only opens maximized, but fullscreen. You know how there is F11 to press? Well why bother, when Autohotkey can do it for you? For me it's a big help with picture folders.

#Home::
Run, c:\a-folder
sleep 300
send, {F11}
return

In this case, Win and Home keys are the combo that makes it happen. But change is AHK's middle name— you can have just about anything else you want. "c:\a-folder" is just an example; it can be any folder you want opened in fullscreen.

The sleep line is a near necessity. If it's not there or if its value is too low, line 4 might not get acted upon, the first time you try the script, possibly even the second time, or so I've noticed on my system. You might need to set it higher still, depending maybe on how many other things your computer has going on at the time.

Related tip:

Within that folder, right-click a blank area and choose "Customize this folder...", optimize the folder (and subfolders if you want) for pictures. Now, there should be an extra option in the View menu, called "Hide file names". Give it a checkmark and the folder's look will become a lot cleaner.