Full image in Popup, Howto

[Handover]

Greetings,

Newcomer here, have no plans to go anywhere else
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end of intro.

I have a problem. I don't seem to get an image display in full size when its been clicked on as pop-up.

Please find in the attached files an illustration of what i will like to achieve, and i forehand thank you for your input.

The original picture is in .JPEG format has the following attributes:
Size : 274 kb, Dimensions 715 x 1074



Pop_up001 is how it shows.

Thank you