I created a simple WordPress plugin to customize the login screen. The plugin consists of three files:

index.php - adds the actions and filters functions.php - contains the functions to customize the logo and page

The plugin itself appears to be working fine except that the logo never appears. When I inspect the elements, everything appears fine, but when I go to the plugin editor, it seems the image was never uploaded. I tried moving it from the root folder to an images folder, but it's just not there. It's a small 80x80 PNG with the file name eotb_logo.png.

Any idea why WordPress would strip the PNG file?