Manager: The site I loading too slow. How can we improve this?

Me: *f5 & look at the network log* the server is taking too long to respond some image requests. We could encode them into the Html to have them all delivered in a single request.

Manager: GTMetrix says we need to compress the images.

Me: *reads GTMetrix report* we would only have a 150kb improvement. It won't even be noticeable.

Manager: If the images take a long time to load, it means that they're too big, right?

Me: or the server is taking a long time to respond our request for them, which is the case.

Manager: compress the images and upload them.

Me: *compresses the images and uploads them* done.

Manager: I don't see any improvement.

Me: if only there was someone who could have predicted such an outcome...