GPT Image 2.5 4K at low costs less than 1024 at medium on Sume

On Sume, a GPT Image 2.5 image at 3840x2160 and low quality quotes $0.0140, less than the $0.0165 for a 1024x1024 image at medium. A 4K frame has 7.9 times the pixels, yet it is the cheaper line item, because the quality tier moves the price more than the size does.

If your only reason for using a small size was cost, that reason does not hold at low and medium.

The grid

Rows are quality tiers and columns are sizes, all as Sume quotes with a one-character prompt. Cells where the larger size is cheaper than a smaller size at the next tier up are the useful ones: compare each low cell with the medium cell in the first column.

Reading the grid

Read down a column and the price climbs by orders of magnitude: from $0.0074 to $0.2635 at 1024x1024, a factor of 36. Read across a row and it rises by a few percent to a few times: $0.0074 to $0.0140 at low, a factor of 1.9, and $0.0659 to $0.1251 at high, a factor of 1.9.

That is why a 2560x1440 low image at $0.0077 costs 5% more than the square at the same tier, and why it is far below the medium square. The estimator multiplies a quality grid by a size term, and the quality grid goes from 16 at low to 96 at max.

When to use it

Take advantage of the pattern in three situations.

• Layout tests. Render at 3840x2160 and low to see how the composition holds at full size for about a cent and a half.
• Print and display proofs. A low render at full size tells you about the crop and the margins before you pay for high.
• Fixed budgets. If the budget is set per image at about two cents, a 4K low image fits, while a medium image at 4K ($0.0325) does not.

Limits

Do not read the grid as a recommendation to ship low at 4K. A lower tier trades detail for price, and extra pixels do not restore detail that the tier did not render. Check a sample against your standard first.

The size has to be sent as pixels, such as 3840x2160, with both edges a multiple of 16, a longest edge up to 3840, a ratio up to 3:1 and a total up to 8,294,400 pixels. The upper bound is what the quote reserves when you omit the size, which is far higher than any figure in the grid.

Large high renders are the exception to the cheap-4K pattern: $0.1251 at 3840x2160 is 1.9 times the square. Use the grid to decide where to spend. Layout work at low is nearly free at any size, medium at 4K costs about twice the square, and high at 4K is the row to approve only for final art.

A quick way to apply this is to write the tier into the stage of the workflow, not the person. Drafts and layout checks are low, review copies are medium, and anything that leaves the building is high after a person has approved the low or medium version. That rule keeps the larger sizes, which look expensive, from being the place where budgets are blown, since the tier does that. Put the same rule in your code review checklist, and when a request names high or max, ask which stage of the workflow it belongs to. If nobody can answer, it should be low.