I think probably attaching the ext. USB HDD in rescue media increases the size of page file thus an increase in size of the backup... just a guess 
My Computers
-
At a glance
Windows 11 Pro 25H2 (26200.8457).core i7 11th gen16 GB DDR4 @3200 MHz- OS
- Windows 11 Pro 25H2 (26200.8457).
- Computer type
- Laptop
- Manufacturer/Model
- Dell Inspiron i5 5510
- CPU
- core i7 11th gen
- Memory
- 16 GB DDR4 @3200 MHz
- Hard Drives
- 1 TB SSD M.2 NVMe
- Keyboard
- Dell Premier Multi-Device Wireless Keyboard and Mouse – KM7321W
- Browser
- Brave.
- Other Info
- Edifier speakers. (Thanks to @Edwin).
-
At a glance
W11 25H2 (26200.7840)11th Gen Intel® Core i7-11700 processor32 GB, 2 x 16 GB, DDR4, 2933 MHz, dual channelNVIDIA GeForce RTX 3060 12GB GDDR6- Operating System
- W11 25H2 (26200.7840)
- Computer type
- PC/Desktop
- Manufacturer/Model
- XPS Special Edition
- CPU
- 11th Gen Intel® Core i7-11700 processor
- Memory
- 32 GB, 2 x 16 GB, DDR4, 2933 MHz, dual channel
- Graphics card(s)
- NVIDIA GeForce RTX 3060 12GB GDDR6
- Hard Drives
- 2TB M.2 PCIe NVMe SSD
