I take it there aren't any too easy posts so here goes:
Say you need a list item query in a page and a new page to unique item view.
You'd want to have a picture, right? But how do you show it smaller on the query? css? not so good...
The best way is to have both a list for articles and a separate picture library for images, and site columns in the list for picture and thumbnail picture.
So, use two fields on list contents, picture and thumbnailpic, where you keep:
picture --> /NewsPictures/pic01.png
thumbnailpic --> /NewsPictures/_t/pic01_png.jpg
SharePoint creates a thumbnail for each picure in picture libraries in jpeg format, 160pixels width.