I understand you absolutely.
Answer is that you CAN'T change any gallery after you click "Submit" button on the TGP. He remember the md5 checksum and you will be deleted or worstly blasklisted (if someo TGP owner will have bad day).
I understand you, that you receiving tons of error, and you likely will have only 20 galleries on your hard drive, than 30, where 15 will have one or more not used recips...
Generally what you are doing isnt good way, for the beginners.
If you are beginner, you MUST buy auto submitter tools. Thay will update own database of 2k TGPs (most important), generate automatically all galleries and insert recip to it, automatically submit to 80 percent of the TGPs and you will only manually submit to the 20 percent of the TGPs.
This submitter SW will generate all sample thumbs for the TGPs, check if you not submitting more than once per day to TGPs, which dont like it (its must to submit more galleries per day, or you will not make big money, start with 3 galeries per day, with different sponsors (recurring!!! not PPS (pay pay SU)), different niches, and select after month, what working the bestly for you, and submit everyday two galeries of this niche + 3 or 4 of the others).
I'm full time gallery submitter, galleries payings mostly all my bills, and i'm personally using this products:
My lowed submitter, im using it 8 hours per day
Firstly buy as the base, TGP/MGP submitter for the 25 USD/month (after several month you will make easy with your recurrings to one year licence, which will save you mone) plus Confirmer (its crazy job, to approve daily 500 emails) for the one time fee of the 29 USD.
So it will cost you now 25+29, and next months only 29.
After several months, when you will be not beginners, you will buy LinkList submitter (its' easy for the professional to make from the one gallery the free site) and Partner account requester (which is needed to claim bunch of the partner account, which is the must for the full-time gallery professional).
But this is the future.
Now you buy the TGP/MGP submitter, make few own gallery templates, fill it with the sponsor content (is good to ask your sponsor, if he may give you 50 unique content sets from the member area (after the time, when you will make more money, he will give you content access to the member area, so you may download content myself), this is important, you need excelent content to be approved!!!), and you may start submit with the submitter software.
It's easy, and don't worry about the messages, which will TGPs show you, some TGPs is full, some not accepting public submitters...
It's only few rules.
1) your galleries must be permanent, you will not delete it, you will not change it, when you click the submit button, the galleries must be absolutely same to the year 2150!
2) minimally 15 pics per gallery
3) only 2-3 links to sponsor
4) special content from the sponsor
and this is all, you will be approved
and remember, do only recurring, not PPS, after several months you will get more from the yours rebils, than from the initial SUs!
So go, buy submitter, and start making money