Photo won’t load

So, new guy here, starting to build the website (First built yesterday, on BlueHost) and I ran across a problem.
This photo: (https://project38.net/wp-content/uploads/cold_panzer.jpg) is a 1024×647, 110kb image that I use in 3 different places in the website. After I was finished editing the webpages, I sent the link to my test computer. It wouldn’t load the images, instead getting something like this: https://i.imgur.com/9nryupE.jpg (pic on Imgur)

I deleted the file, re-uploaded it, and it seemed to fix the problem. My question then is this: What happened, so that I can prevent it ever happening again? The appeal to my website is TANKS and if i have no pictures of TANKS it’s not very appealing.

Thanks!
-T.Ankmann

The page I need help with: [log in to see the link]