Root How do themes work?

[bmkindoll]

When you download a theme it is XX.XMB. Does that amount get added on to the original ROM, or does it replace the information in the original ROM?

The reason I ask is because I have always been curious as to if a theme in theory would slow down a ROM? I mean I know that even if it did it would be so miniscule that nobody would surely notice, but I'm curious just the same.

Thanks

Brandon

 

[whenbrokenx]

I may be wrong here because I'm not a themer but I've seen similar questions like this addressed before in the forums. I don't think themes slow down ROMS at all. From what I understand they are just adjustments to the framework and in most cases changes and additions to/or XML images. With the case of the images, i believe they are just replaced, the theme isn't doubling the images you have, just replacing them. Such as the battery images in the notification bar...stock has one look then a theme replaces those stock images with a new look of images so the stock images aren't there anymore. So in a nutshell themes shouldn't slow down the ROM. I'm sure a Dev could explain things better but hopefully i shed a little bit of light on things for you.