Every Repost uploads your Item's photos again, and every upload passes through a Photo Modification. If each Repost worked from the photos the previous Repost uploaded, those small changes would stack: after ten Reposts the photo would be ten modifications away from what you shot.
They do not stack, as long as Thriftly holds a base photo for the Item. It keeps that base and modifies it instead, so each Repost drifts once from the same starting point rather than once more than the last one.
The clean base
The first time Thriftly sees one of your Items, it keeps a copy of the photos Vinted was showing at that moment, unmodified. That copy is kept for the Item and every replacement that follows it: when a Repost replaces the Item, the replacement works from the same base.
The copy is never refreshed. That is deliberate: once an Item has been reposted, the photos it serves are already modified, so replacing the base with them would defeat the point.
Whenever a base is available
A Repost uses the base whenever one is available, and falls back to the current Item's photos when none is. Two things limit how clean that base is.
Thriftly can only keep what Vinted showed it. If you had already reposted an Item — by hand, or with another tool — before Thriftly ever observed it, the copy it kept is whatever state those photos were already in. It is still the base every later Repost works from, so nothing compounds further, but it is not the photo as you first uploaded it. Only an Item Thriftly saw before anyone reposted it has a genuinely clean base.
Storage can be full when Thriftly first sees an Item. Then no copy is kept at all, and Reposts of that Item work from its current photos, compounding in the usual way. See below.
Either way Reposting itself still works, and nothing you need to do changes.
When storage fills up
Your plan includes a set amount of Photo Storage — a standing limit, not a monthly one. It does not reset at the start of a billing period; it fills as you list Items and frees up as they go. See the pricing page for what each plan includes, and your dashboard's Photo Storage card for where you currently stand.
Identical photos count once. If the same photo appears on several of your Items, it occupies one slot.
Space also comes back on its own. Once Thriftly sees that an Item is gone from Vinted — sold or deleted — it holds that Item's photos for another thirty days, enough to cover a cancelled sale, an accidental delete, or a change of mind about relisting, and then removes them. The thirty days run from when Thriftly noticed, not from the sale itself. If a new Item needs room and there is none, Thriftly clears out those held-back photos first, oldest activity first, and only as many as the new Item needs. Photos belonging to Items you are still selling are never cleared to make room.
If every slot is held by Items you are still selling, there is nothing safe to remove, so the new Item is simply not given a base. The Repost you were making still goes through; Thriftly tells you afterwards that your photo storage is full, with a link to upgrade. Nothing on Vinted is affected, and nothing needs undoing.
Across your Workspaces
Photo Storage belongs to your Account, not to one Workspace, so every Workspace you have draws on the same pool. Adding a Workspace does not add storage. See Billing & Usage for how plans and limits attach to your Account.