Can't upload Product images; database is the culprit, even tho' images stored in File system

Running nopCommerce 3.2. Using FILE storage instead of database (since the site was setup).

Was able to upload image files, both on Topic pages as well as for Categories & Products as late as Friday (was running on a shared SSL during development).

Now, whenever we try to upload a an image file, we get a simple "<Filename> <XX.XXkB> Failed" error message displayed below the "Upload a file" button. The only change that I'm aware of is that I installed a dedicated SSL certificate a few days ago.

<Edited after initial post>
I've checked that the IUSR user has read/write/create/delete permissions to all the required files and folders listed at https://www.nopcommerce.com/docs/79/installing-nopcommerce.aspx

Also, I've noticed that there is NOT an entry generated in the System Log when this error occurs. I'm now suspicious that the error is occurring in the browser (i.e. jscript error). I've tried Chrome, FireFox, and IE; get the error in all of them.

After more troubleshooting, I've determined that there's something about the database itself that's causing the error.

I saw a post about a database hitting its quota and causing this error, which is what made me think to check. However, I've tested both locally (running a local copy of the DB) and remotely, and still get the same error.

Here are my troubleshooting steps thus far:
1. Installed a local copy of nopCommerce 3.2, which has a database named "nop32_Sample" on my local SQL Server. Changed the method of Media Storage from Database to File.
2. On my local site that's won't allow file uploads, I opened \App_Data\Settings.txt and changed the database to "nop32_Sample"
3. Logged into my "problem" local site, running off of the DB nop32_Sample, and attempted to upload a file. It worked!

I've looked at my "problem" site's database and confirmed that both it and its log can grow unrestricted.

What else could be causing the database to cause this problem?

Narrowing it down. The "Failed" error is only occurring when adding pictures to Products. Any ideas?

Figured it out. It was a super obscure problem, but thought that I'd share anyway.

Awhile back I was performing some batch work on the database, while importing products from another website. During the course of said work, I turned of the Identity property of the Picture.ID field.

I had simply forgotten to turn it back on. So, when nop tried to create a new record in the Picture table, it'd fail immediately since the ID wasn't an identity field.

Doh!

I'm having the same issue that you had. Please could you elaborate on what you mean by "switching on the identity of the ID field"?

'SET IDENTITY_INSERT table ON' is a low level database command that allows one to then insert records with your own ID column value rather than letting SQL Server auto-increment it for you.  I.e. 'ON' disables the auto-increment (allows you to insert identities). Setting to 'OFF' puts back the default behavior for an IDENTITY column which is for system to assign it.