- Image Size resamples the image to change it's size.
- Half Size quickly resamples the image to half it's sizes.
- Canvas Size changes the size of the document without resizing it's contents.
- Fit Canvas to Layers changes the document size so that all parts of the image are fully visibly.
- Fit Canvas to Current Layer sets the document size to the size of the current layer.
- Fit Canvas to Selection sets the document size to the bounding rectangle of the current selection.
Documentation Layers Menus