drupal: how to assign the presets imagecache to different outputs of the modules?

I have a drupal site to continue from another programmer, What I recently can't figure out what to do is where it is assigning the presets from imagecache to the blocks for example I have last news post开发者_运维问答ed - uses a preset from the image posted on the article then on the front page i have a gallery with some articles that uses other preset , and so on.. I just can't figure out where are assigned..

In Drupal they are defined in numerous places.

1. In configuration: Admin › Content › MyContentType › Display Fields.
2. In the theme functions. e.g. a function called theme_mymodule_someblock() would return rendered HTML. Inside that function, imagecache can be called to generate an img-tag. Search for theme('imagecache',...).
3. In template preprocessors: e.g. many themes will override the user-picture preprocessor to build their own. Aquia has an example of such a preprocessor. In those processors you will then see imagecache being called trough theme('imagecache', ...) to build an img tag.
4. In the template files often themers decide to ignore all above, ignore all settings and preprocessed and defaults and simply print a theme('imagecache', ...) result in one of the many tpl.php.