My website project's images get uploaded with capitalized filename. Why is this happening?

so strange problem.

I finished my website and pushed the project to github.com. The picture section of my page won't work because the pictures are added into the html with .jpg but github has it as .JPG (capitalized).

So if you go to my site: http://ift.tt/2oUg6N1 you won't see the pictures. However if you click on one of the missing file icon you will get the link to the full picture (but it say that the page does not exist because filename is written in lowercase letter (as it should be) but github has the images capitalized (.JPG)

If you edit the link like so: /Frodo/images/pic4.JPG (sry have to shorten that I can't post more then one link) it infect works.

So what is this problem? On my local machine it's fine. I uploaded it on windows with the github shell like normal.

So I go to my local images folder and I see the filename like so: pic4.JPG --> If I right click it properties it says pic4.jpg

So I renamed it to pic4.jpg and after hitting enter I got .JPG again. I deleted the whole file ending enter. Rename it again and write .jpg and enter --> Now it's actually pic4.jpg.

But how can I push it to github, because it does not recognize it as changed file?

Also how can I solve this for feature pictures and uploads?

Bonus: Cute dog pics on my page :P

Thank you!