Image module for photogaleries
The Future of Image in Drupal 7 reports the following text:


  Image module is being put into core, but not in its current incarnation. Drupal 7 has already made several major improvements that will make handling images (and files in general) much easier, eliminating a lot of the existing code from image.module.





  The Drupal 7 core plan is as follows:
  
  
  Move ImageAPI into core to provide better support for toolkits such as ImageMagick (done).
  Move ImageCache into core to provide thumbnailing abilities as part of image.module (in progress).
  Move FileField into core as file.module.
  Move ImageField into core as part of image.module.
  


This means that most of the functionality of those modules are already integrated in Drupal 7.
ImageAPI still contains code that has not been merged with Drupal 7 code; you should install it if you need the ImageMagick toolkit it implements, or the unsharpen mask action.

As gallery modules, you can try:


Galleria
Fast Gallery
Galerie