One of my clients has sent me a report generated from gtmetrix.com/ about their site. In this report it states the following:

The following image(s) are missing width and/or height attributes.

Then it lists the Front Page Slide Show Images and thumbs as missing width and height attributes:

www.domain.com/components/com_fpss/images/picture1.jpg (Dimensions: 950 x 230)
www.domain.com/components/com_fpss/images/picture2.jpg (Dimensions: 950 x 230)
www.domain.com/components/com_fpss/images/picture3.jpg (Dimensions: 950 x 230)
www.domain.com/components/com_fpss/images/thumbs/picture1.jpg (Dimensions: 100 x 24)
www.domain.com/components/com_fpss/images/thumbs/picture2.jpg (Dimensions: 100 x 24)
www.domain.com/components/com_fpss/images/thumbs/picture3.jpg (Dimensions: 100 x 24)


Although I have Front Page Slide Show set to upload pictures the exact size that they are without changing the size, the output is not declared in the html.

I need an informed opinion for the client that it's not that critical for the image height and width to be input for the image, especially when the image is the correct size. They somehow believe that this may be causing a slow down in their site.

Can someone with experience in this area of development please comment on this?