Frames can be locked in four manners: aspect ration, position, rotation and size.

Locking Aspect Ratio
Images have an 'aspect ratio,' a measure of their width compared to their height.

Frames in FotoFusion contain images, and can be resized.
By default, the frames can be resized to have any aspect ratio. This allows you to crop an image by changing the aspect ratio of the frame.

Most of the time this behaviour is desirable: you can crop an image by changing the frame size and shape to only show an interesting part of a larger picture. You can also make frames of identical size and shapes to create an interesting composition, regardless of the size and shape of the images to be inserted into them.

However there will be occasions when it is important to preserve the original aspect ratio of the image (or to lock the aspect ratio of a cropped image during resizing).

Toggling Aspect Ratio Lock
To lock the aspect ratio lock of an image (meaning the ratio of width to height cannot be changed), select the frame and press the A key on your keyboard. This action is specific to the selected frame(s).  If you wish to select all frames, then do not select any, and hit Ctrl-A on your keyboard.

When the aspect ratio is locked, images can only be resized by their side resize handles; corner handles no longer appear. You can increase or decrease the size of the image, but only proportionately. The shape of the frame will no longer change.

If you wish to turn the aspect ratio lock off, hit A again while the frame is selected.

Showing all of the image all the time
If it is important to you that an image is not cropped,

Now you will be able to move, resize and rotate images but not change their aspect ratio or crop pixels via resizing.

See also the definition of 'elements'.

NOTE: These tips do not apply to the CANVAS BACKGROUND frame. Unless your canvas is exactly the same aspect ratio as your image, part of the image will be trimmed. You can resize the frame to expose the image, but you will have areas of the canvas that will be blank.

Respecting Aspect Ratio when AutoCollaging
When using the AutoCollage feature, you can choose to turn on the "maintain aspect" checkbox. This will place all selected images on the canvas without cropping them. Because FotoFusion cannot crop the images, there will be empty canvas space around the images, unlike an AutoCollage that does not have this feature selected.
 

Locking an Image's Position
If you do not want your image to be moved from a particular location on your canvas, select the Image frame, and right-mouse down to expose a list of options. Select LOCK POSITION. You will no longer be able to move the image, but will be able to edit and resize it. Reselect the right-mouse option to uncheck this feature. Note: AutoCollage overrides Lock Position.
 
Locking an Image's Rotation
If you do not want your image to be moved from a particular rotation, select the Image frame, and right-mouse down to expose a list of options. Select LOCK ROTATION. You will no longer be able to rotate the image, but will be able to edit and resize it. Reselect the right-mouse option to uncheck this feature. Note: AutoCollage overrides Lock Position.
 
Locking an Image's Size
If you do not want your image to be resizable, select the Image frame, and right-mouse down to expose a list of options. Select LOCK SIZE. You will no longer be able to move the image, but will be able to edit and resize it.  Reselect the right-mouse option to uncheck this feature. Note: AutoCollage overrides Lock Position.