So recently I've added achievements (badges) to my wiki and started customizing them to reflect the topic of my wiki. Changing the names of those badges was no hassle and I've done that already, but changing the images of the badges is an issue. I've made sure and confirmed that the shape of the image fits within the badge frame, and they're all supported file formats (as in, they are .jpg or .png files). Yet, when I tried to choose a file and save it within the badge, the site gives me a rather weird notification saying "[object Object]" and the chosen file gets removed. In this way the entire process fails.

Here's a screenshot to let you know what exactly is happening:

I click on 'Choose File' to customize the picture, select a file of my choice and click on 'Save Picture'. Even though the image is a completely supported file format, the process fails and the site gives me a notification saying "[object Object]", and it doesn't really make sense and I don't know what to deduce from such a notification.

Is this perhaps some sort of bug, or is it just me doing something wrong? Please let me know, thanks.