The problem appears to be that the aspect ratio of the cell in your print module is different than the photo, which you say is 6x7.
As I suspected, the image and the cell are different aspect ratios.
For the Photo aspect ratio is 7 / 6 = 1.167
For the Cell, aspect ratio is 24.94 / 18.59 = 1.342
In your first image of you original post, the photo is not "stretched" but is zoomed to fill the cell, height and width. In order to fill the cell the width of the photo is zoomed to 24.94 cm. With an aspect ratio of 1.167, the height of the photo will zoom to 21.37 cm, (24.94 / 1.167) which is larger than the height of the cell, so some portion of the photo must be cropped off both the top and bottom of the photo to fit into the cell.
In your second image, the height of the photo is sized to fit the height of the cell at 18.59 cm.. This makes the width of the photo equal to 21.69 cm (18.59 x 1.167) , which is smaller than the width of the cell by 3.25 cm, leaving an extra white area (Border) on each side.
In order to get the entire photo in the cell without cropping or without extra white space, the aspect ratio of the cell must be exactly the same as the photo. I suspect that the photo aspect ratio is not exactly 6 x 7 as you state, but perhaps slightly different.
It looks like you have set your paper size to 8 1/2 x 11, so your first image is the only way you can get to equal borders all around. If, however, you do not like how it is cropped, place the curser inside the cell over the photo and drag the photo up or down to change the position of the image in the cell.
With a 6 x 7 image, you have only the 2 choices that you posted, either equal borders, or the entire image, but not both. It is against the laws of physics.