PNG Images Appear Blurry in Gallery

Hi,

It seems that whenever I import PNG images to my phone, they appear blurry and pixelated whenever I view them in the gallery. However, they look fine on my computer and in Google Drive (whenever I upload it). This issue didn't arise until I updated to 5.0.2, and I thought it was going to be a one time thing, but still, the images appear blurry and pixelated. Zooming in and out of the photo doesn't help, either.

Does anyone know how to solve this problem? Nearly half of my photos are in PNG, and I'm pretty sure converting them all to JPEG will take a long time (and it will be quite a hassle, too).

I've attached sample photos of my problem (don't judge. I have my own likes, too :o). First photo is when it is viewed in the gallery app, and the second photo is when it has been uploaded to Google Drive. It's very weird, too, because my screenshots are all in PNG and are clear and sharp when viewed, and yet when other PNG images are viewed in the gallery, they appear pixelated.

Hoping someone can help!