A fade, not a seam
Everywhere else on this site two pictures meet along an edge — touching, or overlapping by exactly the strip they share, with a cut or a short feather where they meet. Blending is the opposite intention: the two are meant to dissolve into each other over a wide band, so the change from one to the other is gradual. The second picture is laid over the first by the amount you choose, and across that overlap its opacity rises from nothing to full along a curve you can see and adjust.
What each control does
- Overlap. How far the second picture slides over the first, as a percentage of the narrower of the two along the blend.
- Midpoint. Where across the overlap the two are at half strength. Move it toward the second picture to keep more of the first.
- Softness. The shape of the fade: even, smooth (eased at both ends) or sharp.
- Outer edges. An optional fade at the border, to a colour or to see-through.
- Saved size. Both pictures end to end minus the overlap, or the first picture’s own size.
A worked example
A 4000 × 3000 sunset and a 3000 × 2000 city at night, left into right. The city is scaled ×1.5 to 4500 × 3000 to share the sunset’s height — enlarged, so the list says it is softer. At a 40 % overlap the two share 1600 columns (40 % of 4000, the narrower width), so the result is 4000 + 4500 − 1600 = 6900 × 3000. With the midpoint at 50 % and the smooth curve, the city is at half strength 800 columns into the overlap and fully opaque by column 4000.
Privacy, specifically
The two pictures are blended inside this tab, and the saved file is drawn fresh from them without their camera details. Nothing about them is sent or kept.
The fade runs straight across, left to right or top to bottom; a fade at an angle is not offered. Finding the overlap slides one picture along the other and never bends either, so two views from different spots will not match everywhere.
Snags when blending two photos
How wide should the fade be?
Wide enough that the eye cannot find where one photo stops. For two different scenes — a beach fading into a city — a third or more of the picture works; for two shots of one scene, the width of the real overlap is enough. The overlap slider sets it as a percentage of the narrower picture, and the midpoint slider moves where the two are at half strength.
What do Even, Smooth and Sharp change?
The curve of the fade across the overlap. Even changes opacity at a steady rate, which can show a faint band at each end. Smooth eases in and out, which is usually invisible. Sharp keeps each photo near full strength for longer and crosses quickly in the middle — closer to a soft-edged cut.
My two photos are of the same view. Can it line them up?
Press Find where they overlap. Small grey copies of the two are compared at every overlap from 5 to 80 per cent and the best one is set, with its match score. It only slides one picture along the other, so photos taken from different spots will not agree everywhere; a low score is reported rather than forced.
Can the outside edges fade too?
Yes. Outer edges can fade to a colour or to see-through over a width you set, which gives a vignette. See-through edges need PNG or WebP; a JPG saves them white.
Why is the second picture a different size from the one I added?
Both pictures have to share one dimension — the height for a left-to-right blend, the width for top-to-bottom — so the second is scaled to the first. The list under the preview gives the scale and says if it was enlarged.
