Drag and drop would be easiest.

Please add drag and drop for adding images to jobs

You can do several things to speed things up.

1. set your image capture or graphics tool, to save your new images in a certain folder. Also, in that folder, create a sub-folder 'old'. eg.
\my documents\new images and \my documents\new images\old

In T7, add your Image row, choose Get Image, choose \my documents\new images, choose your image.
(The next time you do this, T7 will have remembered your 'new images' folder)
(Set up a shortcut on your desktop, to your 'new images' folder, use this to periodically click and drag your 'loaded' images to your \new images\old folder. You can also do this directly in T7's Get Image window).

2. If you tend to add images to a lot of jobs, consider setting the 'Image' row, to the New Job template. To do this go to Control Centre/set up wizard/new jobs, tick 'change', then Add. You wont need to make use of the image row on all jobs, but to add an image to your job, you'll only need to dbl click the lineitem (or press Enter).

Incidentally, you can VIEW populated images on a job at any time, edit mode or booked out. Simply R click the image row, choose 'VIEW IMAGE'.