Hi Serellyn,
Sorry you are having problems, and for the delay in getting help!
Would you be able to upload the whole logs folder for me? I would like to look for some clues as to your specific problem. Those PNG errors you pasted above, although look very similar to some other problems we have seen with PNG, are actually not really errors, they all appear near the top of your log file as part of loading and are simply a warning and symptom of us not distributing default UI content that we do not use :).
I’m guessing that you have already found the logs folder but here it is anyway for convinience
C:\Users\USER.NAME\AppData\Local\UnrealEngineLauncher\Saved\Logs
If you could simply zip up the folder itself and upload it here I will get on to investigating your issue asap!
Thanks for your patience
Leigh