Whilst there is not an explicit gesture to “jump” to the bottom of the page, you can easily and quickly scroll down through a long page in most Apps… including Photos.
As soon as you swipe upwards (to scroll down), a narrow scroll-bar appears at the extreme right-edge of the screen. Touch-and-hold the bar - and the bar will thicken; without lifting your finger, drag the scroll-bar downwards to rapidly scroll down the page. Likewise, dragging upwards scrolls back up the page. The presence of the scroll-bar is often (and easily) missed.
The visual length of the scroll-bar provides a relative indication of how much of the extended page is visible on-screen. The longer the page, the shorter the scroll-bar. The position of the scroll-bar in relation to the edge indicates your position in the page.
Try this out on this page - and the scroll-bar will be about a half of the length of the right-hand edge of the screen. At time of writing this reply, this indicates that you can see about a half of the extended page on the screen. As more replies are added here, the page gets longer - and the scroll-bar proportionally shorter.
I hope this insight proves to be helpful in effectively navigating pages on your iPad.