I have been using CC for over 12 years and I have never had an issue putting pictures into my emails until the last two weeks. When you click on the "replace" button for inserting and image, it just closes the dialog box. This is not and will not do.
I apologize that you are experiencing this in the editor. In order to assist we may need more information.
Here is a fix we find works with this type of issue:
We have the same issue using Chrome. Just started in the last few weeks and now an issue with every image block where we are inserting a library image.
The process is to add an image block > save the template > refresh the screen > replace the image block with a library image and repeat.
This happens with any type of image - jpg, png etc.
If I want to add another I have to go through that whole process again.
Takes ages and slows down creation significantly. Why do I need to leave a template in order to edit it again?
Have you tried any connectivity troubleshooting, such as cache clearing or disabling your Chrome extensions to see if any of those are conflicting with the site?
Yes, I have tried all of these. This is the same issue as the original poster. You want to change an image and when you click on the replace image link, the dialogue box disappears and you have to save and refresh the whole page. This is an issue with CC, not with browsers.
And you also tried the troubleshooting explicitly mentioned in Adelina's earlier comment? Since I was unable to recreate the issues you're describing while in your account, I recommend calling our general support line so they can screenshare and troubleshoot the issues as its happening live with you.