I have a canvas size of 72 by 24 inches dimension. I have an image that I wanted to make the same size as the canvas, but whenever I drag it maintains the aspect ratio. Because of this I could not fit the image into the canvas size. What shall I do?
Hold Shift while dragging.
To make matters easier, you can also use the Options bar just below the pull-down menus (Window > Options to make it visible if you don't have it already) to lock or unlock aspect ratio while transforming: the option bar shows W(idth) and H(eight) percentages. Between these two fields is a chain icon which can be broken or closed. If you click it, you toggle between the two states, with the unbroken chain meaning the aspect ratio is locked, and the broken chain meaning it's free.