How to places images across page

This somewhat depends on exactly how you want to add the images.

The ‘quick-and-dirty way’ would be to use a plugin that lets you insert tables into a post and manually insert each image into a cell in the table. Two such plugins:

CKEditor

Ultimate TinyMCE

The ‘add-images-automatically way’ will require coding a template to retrieve posts with the images, say from a certain category, and display them in rows. Then, to add an image, you would just create a new post with the image and assign it to the correct category.

Here is an article with some sample code for displaying posts in rows:

http://wordpress.mcdspot.com/2010/11/28/align-posts-in-a-row/