After coming back from a holiday to Europe I had several thousand photos on my iPad. I had already synced to the Mac, and now needed to delete them from the iPad. The only method I could see would be to turn off syncing. But that also meant that photos I wanted to keep on the iPad got deleted as well. I could have done that and just resynced the images I wanted back to the iPad, but I wanted to just remove some of the images. Looking in the Photos app I could not find any method for bulk selecting the images I wanted to delete. I tried several things and eventually found some tricks.
Trick 1: Multi-selecting images. Normally you tap an image to select it for emailing or deleting. I found that if you tap and hold your finger on the image for a second or two, you can then drag your finger across other images and they will also be selected. Using this I could quickly select many images by just running my finger backwards and forwards across the rows of images.
Trick 2: Scrolling and selecting images. The next thing I was looking for was a way to select images, scroll to the next page and select more. I found that using Trick #1, I could select the images currently visible on the screen. I then found that once I had selected the images, if I left my finger on the screen and used my other hand to do a scrolling motion, the iPad would scroll to the next page of images, and still leaving my "selection" finger in contact with the screen, I could keep swiping across the images to add to the selection.
This method is nowhere near as fast as a 'Select All' function - which we don't have. But it's a lot faster that manually tapping each image.
[crarko adds: I haven't tested this one. I imagine it should work on other iOS devices as well.]

