Here is the problem of a blogger:
"Your site is great. I am hoping you will help me with what must be a simple problem. I read your article but my template has the sidebar width as 66%, not px, so percentages instead. Something I did in my sidebar stretched it out and consequently my images look stretched and the whole blog looks less professional. Any chance you could have quick glance at this and tell me how to get it back to a reasonable width? I think the "oveflow fix" may have something to do with it. I must have added something too wide."
Personally, I prefer a fixed width template as I know exactly how my blog will look like irrespective of the screen resolution of the visitors, plus I know exactly the maximum width of photos, scroll boxes, etc. to put in the post or sidebar to accommodate those with small screens as if I put too wide an element, it will make the blog awful to them. You may read about some of the reasons in my post What is the best template for my blog?. As more and more surfers upgrade to large screen, I may change my mind, but I doubt it as I think small screen will always be with us because of laptops.
Anyway, I checked the blog of the blogger who had the problem mentioned above and see not distorted image. I took a screenshot to show you what I mean:
I suspect the blogger may be using a wide screen as they are becoming more popular nowadays. With wide screen, if you chose the wrong screen resolution, your images will become distorted (stretched). A skiny fellow may appear like a fatty. I would suggest to that blogger to try playing with the screen resolution to get the proper resolution so that the image will not distorted (stretch).