If you’re putting together a rig for generating images in 2026, you’re basically choosing between these three families. SD1.5 is the old guard from 2022—lightweight, trained at 512, and the whole ecosystem grew up around it, so you’ve got the most LoRAs, checkpoints, and ControlNet support.
SDXL came in 2023, native 1024, bumped parameters to over 3 billion, and took prompt adherence and realism up a notch—it’s the sweet spot for “decent quality without insane VRAM.” Flux has a different architecture, a flow-matching transformer instead of UNet, and it’s the most powerful but also the most VRAM-hungry.
From my experience, you need at least 16GB to mess with Flux or stack LoRAs on SDXL, and 24GB+ to run Flux comfortably. If you’re on a budget, just stick with SD1.5.