Why do some pictures differ in size when reading from a phone

I have a few pictures that were made with a different phone and uploaded to my laptop.

When reading the details of the file, the size of these pictures is different between my phone and my laptop.

I checked it on a different phone and both phones (samsung Galaxy S5 Neo & Motorola Moto G5) show the same size.

It isn't much, but the strange thing is that it doesn't happen for all the pictures, only a few.

Can anyone explain?