The Pill That Cures

How do you embed your image in your blog ?
Which is the best way to post high-quality pictures ?

I tried these :


Exported out from Lightroom with SRGB, 800 by 640.
Upload to Picasa , and chose Large Size for embedded image.
Made photo to match the width for the column here by setting ' witdh="100%" ' in the HTML


Exported out from Lightroom with ORIGINAL setting (as taken by camera)
Upload to Picasa , and chose Large Size for embedded image. (it seems like Picasa does not allow embedded image more than 800 px ? )
Made photo to match the width for the column here by setting ' witdh="100%" ' in the HTML


Exported out from Lightroom with ORIGINAL setting (as taken by camera)
Upload to FLICKR , and chose Largest Size 1024*685 (I dont have pro-account at this moment)
Made photo to match the width for the column here by setting ' witdh="100%" ' in the HTML

Questions:
1) Does setting 'width=100%' to match my blog column affect the image quality , or even create better quality since bigger image are squeezed to match the column size ?