The easiest way is to resize all your small jpg files to the same height (you can use "image size" command), i.e. 111 pix.
Then use the black arrow tool, click the small jpg then drag it to the main canvas. They will automatically create new layers for individual pictures.
Oh, for best result, don't forget to create the guide lines by clicking on the ruler, then drag it to the edge of individual pics, to exactly line up with the next pic. Then choose the snap to guide/grid option, so no layer will overlap one another.
After arrange all your pics on the same canvas, you can change your canvas size to delete leftover space, then "flatten the image".
Hope that helps
Hybrid Mode
