Maybe I'm getting old. Strike that -- I'm definitely getting old. But maybe I can't remember when I snapped a particular iPhone shot because I'm getting old. Or maybe it's because of the sheer volume of photos I keep on my phone. I like to think it's the latter.
Regardless of the cause, there is a solution: Handy Album. This free iPhone app lets you view the Exchangeable image file format (EXIF) information of your photos, so you can see when, where, and how you snapped each shot.
Handy Album doesn't boast the most intuitive UI, but the app is free and not too difficult to navigate once you get the hang of it. You'll likely see two thumbnails when you first launch the app, with two buttons in the upper corners and a row of three more buttons along the bottom. The photos are grouped by day; if there is more than one photo for a given day, you'll see a number in the upper-right corner of the top thumbnail telling you how many are in the stack.
Tapping a thumbnail lets you view it in full screen. Tap again to view the EXIF information. Tap again to hide the EXIF info, and tap a third time to return to the Back, Sharing, and Open in buttons.
If you tap a stack of thumbnails for a given day, they open as a grid of six thumbnails. You can swipe to the right to view more if there are more than six for the day in question.
You can also tap the middle button along the bottom row to browse all of your photos via this grid view. Whether viewing a full-screen photo or a grid of photos, swiping twice to the left starts a slideshow.
Tap the left button with the globe icon to see Handy Album's map view. A single tap zooms in, while double-tapping a thumbnail opens a photo or stack of photos.
Tapping the sun icon in the upper-right corner lets you view your photos by year. Tapping the magnifying glass below the by year options groups all of your photos across the years together.
You can snap a photo using the app, but it doesn't offer any features you don't get from the default camera app.
Lastly, when browsing your photos, a swipe up reverses the chronology of how they're sorted.
Handy Album is a bit odd to navigate, so I doubt you'll use it to share photos or snap pictures, but it is, well, handy, to look up when and where a shot was taken.