Why is the JPG not visible?

Question

JavaScript

Site on the node, I insert pictures of the form:

<img data-reveal-id="showFullPhoto" class="small-img" src="/images/content/8127.jpg">

Some photos show, some don't. All the photos are in the content folder. Help, I don't understand why.
for example

<img data-reveal-id="showFullPhoto" class="small-img" src="/images/content/8125.jpg">

Shows without problems. 8125.jpg and 8127.jpg in the same folder.
Before that, perhaps the photos were of different types: .jpg and .JPG, could this play a role? Both files open locally without problems.

Answer 1

The problems were on the side of the host. Everything worked.

Answer 2

And if you remove data-reveal-id ?