I have an issue where I am trying to upload images for the favicon and transactional email within Magento admin.
Some images I select upload as expected and show the preview, however some images just don't upload for some unknown reason.
The image file type is supported and is the same as the images that seem to be uploading correctly.
At first I assumed that it was an issue with the images so I re-created / saved these and tried to upload but had no luck.
What could be causing this and how can I resolve the issue?