GPT will not be usable by XP and earlier systems (I think), so avoid it if that is an issue. Not having seen an XP machine in 3 years it's not an issue for me so I use it in preference to MBR, but it makes little difference at this point in time. At some point, you will have to use GPT, until then, make a choice.
Let's be careful about drives vs. partitions. A drive is an entire physical storage device: a hard disk drive. A drive is something you can hold in your hand.
The storage space on the drive may be divided up into one or more partitions. Partitions are not drives, they are sections of drives. You cannot hold a partition in your hand.
GPT and MBR are drive-level partition table formats that affect the whole hard disk drive. It's how you tell your system what the partitions on the drive are, how big they are, and where they start and end.
The ancient partition table format from the 1980's IBM PC BIOS firmware era is MBR. The modern format from the 2000's Intel [U]EFI firmware era is GPT.
A drive could either have only an MBR table, or it could have only a GPT table, or it could be a hybrid containing both.
One form of hybrid is primarily GPT but has a "Protective MBR" or "PMBR": a fake MBR that tells non-GPT-aware software that the whole disk is allocated to an unknown partition type. This keeps non-GPT-aware software from thinking the disk is unformatted and trying to format it.
Another form of hybrid is a disk that has both a GPT and an MBR, where the formatting/partitioning software has tried to keep them both in sync. So MBR-only software learns about all the same partitions that GPT-only software learns about.
You can make a GPT-only drive into a hybrid, but since this concept is at the whole-disk level and not the individual-partition level, you can't make a single partition be MBR.
Partitions have a different set of formats, such as FAT32, ExFAT, NTFS, HFS+, and others. These are choices that affect individual partitions, not the whole disk drive.
Best Answer
It has nothing to do with GPT or MBR. Partitions can't span over multiple disks. One disk can hold multiple partitions, but not the other way round.
The Images partition doesn't have any drive letter assigned. Unless you have attached it to a NTFS folder, it looks like it's inaccessible. Now, it may be a recovery partition, in that case you should absolutely leave it alone. The only solution is to buy a bigger disk and clone your current one.
If you're 100% sure you don't need the Images partition, you can delete it to recover slightly over 6 GB of space it occupies. Then you'll be able to expand C: drive to that space, but you'll have to do that without Windows running, because you can't resize a file system in use. You can for example boot off a Ubuntu flash drive and use GParted to do that.