Hi simplewebconsult,
Thanks for the information and bug report.
1.- You could re-generate the images from the admin panel, not sure if that will add the watermark or remove it from all, I will test later and tell you how it went.
2.- That's already on our bug tracking system, we'll fix it
3.- Where/When/How did you get than error? I'll check if the form are sending GET or POST data, probably you're right and I missed some GET instead of POST
4.- True, as far as I remember, that panel will only check on the payment table, need to add some check on premium one
5.- We also offer an IPN solution. First, with the direct access of the API we should know if the transaction is OK or not at the same moment the payment is processed. But if for some reason that fails, we offer an IPN file which will handle the payment asynchronously.
Current workflow :
1.- User make a payment
2.- Redirects to your site
3.- Your server access the information with the API (OK, cancelled, or some other problems)
4.- If it was OK, paypal registered the transaction on their servers, your site does the same (adding it to the Database)
5.- Right after that, paypal (if you configure it to do so), will try to contact your IPN file (provided with the plugin)
6.- IPN file will check if the payment is processed on your server and process it if it wasn't done before.
7.- IPN file should return an OK to paypal, if this OK is not returned, paypal will try to contact your IPN until it's done or two weeks have passed.
If everything is ok, you will stop at half of the step 6 (when the IPN check against your database and see the payment have been processed before).
If step 4 failed, then step 6 continue the transaction process (it's done right after the payment is made on paypal)
If step 6 fails, paypal willl try again and again for over two weeks, so unless your ipn file is down for two weeks, your payments should be processed correctly. Of course, some errors could happens, but we hope they don't.
Again, paypal will try to contact you IPN right after you made a payment (usually, paypal wait 5 seconds before redirecting you back to the store, so in those seconds, they have the IPN job done). If that first attempt failed, they will try once per hour (several times), then once per 3 hours, then 6 hours, 12, and once per day until two weeks. It's a good idea to have a few options to control it manually and made corrections, we'll add them!!
6.- OK, I think that's a great addition
For your information, there's no need to add funds to Paypal, you could create a "sandbox" account, that will let you create some ghost users' accounts with money, to test the transactions. You should find more information on sandbox.paypal.com We also provide some flag to turn on/off the sandbox status.