Icon image uploading differently?

I created my own social icons, saved them as .png and uploaded them to my library. The issue is that one particular icon is showing up differently in my library.

It appears smaller, though the dimensions (75px x 75px) are the same. I used the same background image for building all of them on PicMonkey, and even have rebuilt the icon again, so I’m a little stumped as to why this one isn’t cooperating.

Anyone know why the icon would be showing differently?

Here are links for a visual:

http://www.enduringepilepsy.com/wp-content/uploads/bloglovin.png

http://www.enduringepilepsy.com/wp-content/uploads/bloglovin2.png