Whether your image has text on it or the picture of a doghouse, the positioning will work the same. You can apply classes or IDs to the code, and then use your CSS to position the image via that class/ID.
However, since you're talking about a text image: It's always better to add text as text. Not only is it easier to update, an image can also not be read by search engines or screen readers. Basically the only good reason to use text images is if you're using a special font for a header - but even then you should always have the text itself presented on the page (hidden by the image, but available for search engines, screen readers, and those with images turned off).