Uncertainty about the size of uploaded images

Hi,

I have a general question about the size of uploaded images. Not the original images that are being uploaded by me and my clients. We all reduce all images in size and quality so that usually the images we upload (depending of the kind of website) are not more than 100-200 kB.

When an image is loaded in WordPress, it is being converted by Enfold into various sizes. I am surprised to find out that most sizes are smaller than the original images, however the weight of most of the Enfold images is far bigger than the original image.

You can see an example of what I mean at following image: https://dutchforstrays.com/image-sizes.jpg. The original image has a size of 960 x 960 px and is 99 kB. From the Enfold size 450 x 450 px, all images are bigger than the original 99 kB. Even upto 319 kB!

How is this possible? Can you explain this to me please?

And, is there anything to do about this? Or what is the best way to work with images in Enfold to avoid these heavy loads? We do our best to reduce images sizes as much as possible before loading, but in the end the (Enfold) images are still very heavy…

Thanks a lot!

Best regards,
Monique