Excerpt feature images bigger than originals?

Hi all,

I’m looking at ways to reduce the load time of my site. Currently at 5 seconds which is pretty reasonable considering I’m on a free server and every now and then the wait time for the server is 1+ seconds. There’s some font-awesomes in my theme and will be looking at them later down the track.

What I did notice was that my images are uploaded around 20kb because I do compression on them before uploading them. I use a great tool called Caesium.

But when wordpress adds them to the featured image box they must get expanded because they go up by about 10-15kb. Currently I have 6 or 7 of them so that’s about 10% of my total page size.

I did have EWWW image optimizer installed but removed it. Would a tool like that rezize the additional size versions of my uploaded images?

Thanks!