If you want to just upload the occaisonal single picture in a posting, this is the simpliest I have ever seen:
https://www.pic-upload.de/
Choose wanted image size
before you navigate to you image you want to upload - that is the only thing you have to take care for. You cannot change image size anymore after having selected an image to upload.
The overlay you currently get is just a request for end-of-the-year (voluntary) donations.