I am placing this question about portfolio in this Lightroom Classic community..

[mrdavie99]

...because when I searched support for portfolio I fell into a rabbit hole.

In order to get some white space around images in my portfolio, I am thinking I have to print to file and then upload those images to the portfolio. Typically, I would upload raw images and let the portfolio app convert them to jpegs, but the resulting images have no white space. Is there another way to create white space?

[Rob_Cullen]

I cannot find a way for "white space" within Portfolio.

Only [Gutter] will set the width of space that divides the thumbnails.

I agree you will have to "Print to file" or [edit in Photoshop] to create image files with a white border (Stroke?).

This screenclip shows two images that have a 'very narrow border' in my Portfolio page-