If you insert the images into table cells of fixed width, the image will shrink to the width of the table cell without the need for a macro and the height of the cell will grow to accommodate the height of the picture.
OR
Add the Format Frame ... command to your QAT (Quick Access Toolbar) and insert a frame to hold the pictures. As with table cells, pictures will shrink to the width of the frame and the height will grow as required. Both can be inserted with or without borders.
If you are doing a lot of work with image captures investigate SnagIt which has lots of useful image editing tools and capture options.
You may also find
http://www.gmayor.com/photo_gallery_template.html useful.