Automatically Set Height & Width Attributes to Attached Images

[Budget101]

All image files in the CMS end up saved as "attachments" but when you view the site NONE of the images have height and width attributes- which makes the page rendering speed Drop considerably.

How/what do I need to modify to automatically pick up the height and width of the photos??

Currently when I create an article, add an image, then click on the pencil to choose the size of the image to display as "Thumbnail", "Medium", "Large " or Full Size" - the image displays but without any height & width attributes.

If I choose thumbnail, this is the info that is plugged in after the image source:

PHP Code:

alt="" class="align_left size_thumbnail" border="0" 


It should automatically include the height & width based on each size (thumb, med, lg, Full)
alt="" class="align_left size_thumbnail" border="0" height="150px" width="150px"

Any ideas how to do that??