I recently changed my featured images to be larger on the home screen which I think I have managed. However in doing so (using the regenerate thumbnails plugin and the colorlib plugin 25 zip) it has changed my slider images to be different sizes.
Also it has made my recent post thumbnail images to be half grey. I tried the CSS code you advised for a similar problem on another thread, however it just caused the thumbnails to stretch and look distorted. It was the following:
So that has fixed the size of the thumbnails, but the first image on my slider is still smaller than all the rest. It has made it smaller and pixelated. All the other images on the slider are fine except the first one.
I want the first image on the slider to be the same size as all the others.