Wrapping text around an image or other media added to a page's content area is a function WordPress provides in the Media Library.
Make sure you read and understand the settings when adding media. These settings will be on the right side of the screen when including any media. There is a size selector (make sure the image is not 100% of the area's width) and make sure the alignment of the image is either left or right, not centered. See this for more information:
Please also note that if you use Wordpress' image scaling options (which work very well), the images will not necessarily be scaled in Internet Explorer or other browsers that do not recognize the code executing this. Some have used lightbox plugins to achieve having a smaller image within content, which then opens a larger one. This usually works.