If you mean positioning them at the right, but in the center or bottom of a text capsule, it can't be done. When multiple photo capsules within a text capsule are aligned to the right, they will always be placed one after the other in the single file you mentioned. But there is a way to make it look like it's centered or at the bottom of your text capsule.
Let's say you have a text capsule you titled "Positioning photo capsules" and you have three paragraphs in that section. You want your photo to be next to the second paragraph and can't do it with a single text capsule. Create a text capsule for your title and the first paragraph and one for the second and third paragraph (without a title). Now when you place your photo capsule to the right of that second text capsule, it will be next to your second paragraph. If you want the photo next to the third paragraph, place that paragraph in it's own text capsule (without a title) and place the photo capsule to the right of that text capsule.
If you do either of those and you preview your hub, the picture should appear as if it's in the center or bottom of a single text capsule.