Remove Excess Uploads

I keep getting this error when I try to use the scheduler. Whether the graphic/video is right from Express, or downloaded and then try to upload it. I have 1 png attached here (which was created using Adobe Express originally) , which would appear to be within the limits of Facebook as outlined. I can't get past this error to schedule and have to post through another medium. I have tried on different devices and browsers. How can I better upload my images?