There are several species of rosemary, and they all can be used for culinary and medicinal purposes - just look for the botanical name 'Rosmarinus officinalis'. The common name for some unrelated plants might contain the word 'rosemary', but aren't necessarily edible - this is why it's so important to learn the botanical names of any herbs you grow. I suspect the 2 plants you saw were one and the same species. A baby plant will have baby-sized leaves - a grown-up will have adult-sized leaves. Right? Also, in many cases with herbs, you can allow your nose to guide you. Don't be afraid to break off a leaf, crush it and smell it. If you had done that with both plants, I'll be willing to bet that they smelled the same. However, you're wise to be cautious. If ever in doubt, ask an expert. Any good nursery will have at least one qualified horticulturist who can advise you.

Where do you live? (state, zone?) Is this a recent photo -i.e., are these growing now? I enlarged each picture a lot. Reading top row, L to R: 1, 2, could well be alyssum but the foliage does not seem quite right to me) but 6 definitely is alyssum (which actually IS an herb - Google it!). I agree with the consensus on #3; looks like grass but if you pluck some of the leaves & smells & tastes like an onion, it is chives. I believe #4 is a petunia (also may be considered an herb due to some ways petunias have been used; e.g., as a tisane- yuck - and the leaves as a pest repellent). Row 2, L to R: Number 5 is haunting me; I should know it, but I think it is something generally sold up where I live as an annual in a hanging basket (like a verbena). Number 7 is thyme; w/o being able to smell it cannot say which cultivar, but it looks like English/French/winter or whatever "ordinary" culinary thyme is, depending on what nursery sells it & what they name it. The last one certainly is a rosemary.

5 looks like a creeping Verbena to me, 7 looks like a silver or variegated thyme (thus the reason we need larger photos) and I agree that 6 looks like alyssum, 8 like rosemary, 3 like chive, and 4 petunia. One and two don't look like culinary herbs to me - perhaps purple and white alyssum? If you can post each of the original photos in its own followup to this post, you should get confirmation.

No you can't switch dried for fresh. Dried herbs have no effect on the pH so can be used at will but fresh herbs will change the pH and move it into the alkaline range so the recipe r processing would have to be adjusted in some fashion to compensate. That's why most legit recipes will stipulate which can be used. Dave