picture resolution

[irvineboy]

I compare two jpg pictures over the years and noticed some changes. I am not a photographer so hoping someone who understands can help.

new picture is 2300 x 3300 resolution. Horizontal and vertical is 300 dpi. Size is 600 kb.

old picture is 2300 x 3300 resolution. Horizontal and vertical is 72 dpi. Size is 2.5 MB

I googled 300 dpi vs 72 dpi. It said that 300 dpi allows you to print the picture and have better clarity whereas 72 dpi is for online images. So my question is, how come the size of the picture decreased from 2.5 MB to 600 kb however, the dpi increased? I thought if dpi increases to allow for better higher quality printing, then the total size of the picture will increase?

 

[ThatTechyGuy]

I am honestly not sure why the image with a higher dpi is smaller in size.

I suspect there’s something that we don’t know about that happened whenever the image was duplicated. Or, are these the same exact picture? The same image that is.