Can't load image to website

I am trying to load an image to my website, but for some reason it will no longer allow me to do it. I have many images already loaded and I just wanted to change the logo.
It shows the hint that the image library is trying to open, but after several minutes nothing loads.
I have tried different themes to make sure that it’s not the theme that I am using, but the problem happens with all of the themes.
I added my Sitemap to Google and Bing today, but I don’t think that is the problem either.
Any help would be appreciated.

Thanks, Carmen J