File upload issue / limited by pixel dimensions?

I am experiencing an odd issue with a file upload.

The CMS isn't properly handling the upload of image files (jpg, png, gif) that are larger than ~5500 pixels wide. It took me some trial and error to figure out this approximate number.

The file is actually being uploaded to the "uploads" folder, but it doesn't show up in the CMS after the process is complete

When it would normally prompt me for the Title/Caption, instead it says "No matching uploads were found!".

The file size itself shouldn't be a factor since the files I am uploading are not very large - approximately 1.5mb

Any thoughts/help?