Adobe Portfolio — Blurry images

I've been using Portfolio for the past couple years for my website, and just today when giving it a refresh I noticed my images aren't sharp when viewed in the Lightbox. All images uploaded are 2500px on the long side, giving more than enough resolution for an average screen, but the fine detail just isn't there. 

Over the past couple days I had been looking at other options for hosting my site (Squarespace, Wix, etc...) and my images there look fantastic! Seems strange using a platform from Adobe themselves, wouldn't give me optimal resolution. 

I've combed through the options for Portfolio and see no way of making any changes other than just turning the lightbox on or off. Is there something I'm missing that's causing loss of image quality? Again, they look great on other platforms (even Facebook and Instagram have rendered them better).