If you want any hope at all of being able to recover the contents of the original Full, do NOT consolidate another backup into that file.
But if you're curious, I'll give you a bit of background on how consolidation works (and why it works that way), as well as my theory as to how you may have ended up here.
Picture a scenario where you create a Full backup on Sunday and create Incrementals on each of the subsequent days that week. You now have a Full backup and 6 Incrementals from Monday through Saturday. Let's say that later on, you decide you only really want to preserve the Saturday backup "state". You no longer need the ability to restore to Sunday or any subsequent day; you just want to be able to recover to Saturday if needed later on. Since you have a Full and a bunch of Incrementals, you can't simply delete the Sunday through Friday backups, since the nature of Incremental backups means that would render the Saturday backup useless. But those intermediate backups are taking up space preserving unique "states" that you don't care about anymore. The consolidation utility offers a solution to this. If you choose to consolidate from the Sunday Full to the Saturday Incremental, the end result will be a single Full backup that contains the "state" of your data as it was at the time you made the Saturday backup. This is called a "Synthetic Full", since you have a Full with contents equivalent to what you would have gotten if you had captured a Full backup on Saturday, even though you didn't actually do that. But it's important to note that the individual "states" of all of those intermediate days are NOT available anymore. (Don't lose hope for your predicament based on what i just said; there's more to the story.) The purpose of consolidation is NOT to preserve multiple backup states in a single file, i.e. you would not be able to use that consolidated backup to restore to your Tuesday state. The purpose of consolidation is to retain only the data from those intermediate backups that is necessary to keep the Saturday backup usable. So for example if you created a 50 GB file during that week and it ended up in your Friday backup, but you deleted it before your Saturday backup, then your consolidated Synthetic Full meant to retain only the Saturday state would not include that file anywhere.
Ok, so how is it that your data might still be there even though I said that the preceding backup states aren't retained? That has to do with how the consolidation operation itself works in order to protect against data corruption if any unexpected events arise during consolidation. Let's take a simpler example involving only a Sunday Full that captured 50 GB of source data, and a Monday Incremental that was captured after you had deleted 5 GB of source data and created 5 GB of completely different data. (Assume uncompressed backup files for simplicity here.) So you have a 50 GB Full and a 5 GB Incremental. If you consolidate those backup files, you do NOT end up with a 50 GB Full even though the net change in source data between the Full and that first Incremental was 0 GB (5 GB deleted, 5 other GB created). You will instead end up with a 55 GB Synthetic Full. Why is that? Because when Reflect performs a consolidation, any data blocks within the Full that are required for the backup that it stores are NOT overwritten. Instead, the Full will grow as needed to "absorb" the new backup WITHOUT overwriting any of its existing data blocks. The reason this is done is because if the consolidation operation fails partway through for whatever reason, the fact that none of the original data blocks were overwritten means that the original, pre-consolidation state of that backup is recoverable. Reflect would just have to ignore the new data blocks from the failed consolidation. If on the other hand the consolidation succeeds, then Reflect updates that backup to actually use those new data blocks, and then any data blocks that aren't needed to retain the NEW state of that backup get marked as scratch space. THOSE data blocks will be eligible to be overwritten during the NEXT consolidation operation. This means that the Full doesn't have to grow by the full amount of every backup being consolidated into it. Instead, existing data blocks can be overwritten, but only if they aren't needed by the current state of the backup.
So, because you've only consolidated one backup into your Full, all of the data blocks from that original state should still be there. But again, I have no idea whether you can actually "resurrect" that pre-consolidation state. And if you can, I expect it will involve assistance from Macrium Support.
In terms of my theory as to how you ended up with an Incremental that seemingly blew away most of your photos, I'm looking at the drive letter confusion and that Backup Set Matching setting I asked you to check. The default Backup Set Matching setting is Similar, which means that as long as an existing backup contains at least one source folder in common with the new backup you're making, then Reflect will allow you to create an Incremental or Differential from that existing backup. But if you change that setting to "All", then Reflect will allow you to make a Differential or Incremental from an existing backup even if the existing backup and the one you're running now have NO source folders in common. That plus the drive letter confusion makes leads me to suspect that your original Full backed up M:\Memories. And then for your Incremental you may have inadvertently backed up only some OTHER folder that contained fewer source files, rather than the same source folder you originally backed up in your Full. Either that or you may have assigned the original drive letter to the wrong drive and backed up a different source folder, even though the path was the same as the original Full. Either way, the result will be an Incremental that essentially says, "The source data includes this one folder [which is different from your original Full] and nothing else, i.e. it does NOT include the folder that was originally backed up in your Full." If you then choose to consolidate that Incremental into the root Full, you will end up with a single backup that matches the state of that Incremental, which contains only that second, incomplete folder and no record at all of the folder originally backed up in your Full. But again, technically the data blocks would still be there, and potentially recoverable.
Hopefully you were able to follow all of that, and either way, good luck!!