Depending on your model of laptop, you can probably get reasonable speed from expansion storage for rarely used images like these.

I opted for the 128GB SSD in my MBP (last 17" model, from late 2011) and a few years later I added a 128GB ExpressCard SSD, which i use pretty much exclusively for (largely Linux, largely via Vagrant) Virtual Machine images. Sure, I'll definitely order a bigger built-in SSD on the replacement, but on a newer machine without ExpressCard you could also use a USB3 flash drive or (if you are on a mac) a Thunderbolt SSD device.