Same results here, seems like a hidden price increase, hopefully they will still keep 2.5 running for some time.

Similar results for my workflow. And the Round art comes out significantly less round without prompt changes (more input tokens)

  Setting (1024x1024)   Tokens   Cost/image   Time
  2.5 medium              439     $0.014     12.0 s
  2.6 low                 824     $0.025      6.7 s
  2.6 medium            1,449     $0.044      7.9 s
  2.6 high              1,758     $0.053      8.9 s

same in my testing; super deceptive marketing here. it’s 3-4x the true cost of 2.5.

Output image tokens per image (2.5 Flare → 2.6 Flare / Sunburst)

low, 1024x1024: 196 → 824 (4.2x) medium, 1024x1024: 439 → 1,449 (3.3x) low, 1024x1536: 158 → 664 (4.2x) medium, 1024x1536: 343 → 1,132 (3.3x)

Same $30/1M output tokens on all three, so per image: low: $0.006 → $0.025 medium: $0.013 → $0.043

from 800 to 1500 is barely 2.

from 200 to 450 is just a little over 2.

Nothing near "quadrupling"