Yes, I could use imgur, but I also could use WordPress, or anything else already existing.
[ispoiler]on that note: imgur has a lot of issues, including not being very accessible, because they play around too much and break accessibility features AND "older" browsers, that DO allow for improved accessibility.[/ispoiler]
Or I could have fun. Because I've started programming as a hobby, just having fun. And I still have fun with programming, after 30+ years. The same kind of fun I'm having, when I do break my fingers and back, while playing around with way too small PC cases 
Another lazy way out would be: Select appropriate photos on desktop, run a quick batch job with a decent image viewer / converter (I use ImageMagick because I'm used to, on Windoze it probably should be IrfanView), and upload everything into a directory located on my website. Its what I considered first, but its just no .. fun. And also not very flexible.
With the recreating of an ancient solution (with its story detailed below), it should be both fun and fulfilling needs 
Once upon a time there was a PHP script doing exactly the same, just a bit less polished, called qig (Quick Image Gallery, if I recall it correctly); it was a self-contained one file PHP image gallery script, that would auto-generate images in all required sizes, plus a quick selection of insertion codes. It was just that, but it excel in its job perfectly. Alas, that was in the mid 2000s. At some point, the author stopped its development, and nobody really took over or created anything similar.
Well, now is the chance to revive this beauty! As stated elsewhere, I AM VERY FOND OF CHALLENGES; and really, I need a get-away from all my regular work - which these days primarly consists of a) figuring out what others did wrong, b) fixing this, and c) improving whatever feature or website part was concerned at the same time. All of that with WordPress, WooCommerce and other E-Commerce heavy-weights (eg. Magento, etc).
Yes, it brings in the money, is challenging in its own rights and ways, but a lot of that not particularly creative or (re)inventing things newly. It also tends to get repetitive quickly, and that requires lots and lots of energy to endure.
