If I understand you correctly, I think ja-thumbnail will let you do this.
You could use an image that is 100px by 100px on your blog view and then 200px by 200px in the actual article.
You could further use something like ja-sidenews to create a list of articles and set the parameters of this component to have thumbnails of 60px by 60px.
<em>@th3who 188020 wrote:</em><blockquote>Hello I am stuck on this please help i want to make an article with a big image. I want a small image to show up in the list of articles but when you click read more the article should show the real size image.
(this forum wont let me upload an image to give an example it says invalid file all image types give an invalid file error)</blockquote>