Bulge and Pinch: Warp One Part of a Photo
Click to place the centre and everything outside the circle is left byte for byte untouched. The displacement and its rate of change both reach zero at the rim, so there is no ring where the warped area meets the rest.
Drop images here
or click to browse · or paste with Ctrl+V
JPG · PNG · WebP · GIF · BMP · AVIF
Click or drag on the preview to place the centre. The dashed circle shows how far the effect reaches.
Everything outside this circle is left exactly as it was, right down to the byte.
Presets
Your photos are never uploaded. The warp and the export both run inside this browser tab.
People also use
Everything this tool does
Nothing outside the circle changes
With a warp at full strength, every pixel beyond the reach is byte for byte identical to the original, not merely close.
No ring at the boundary
A squared falloff makes the displacement and its rate of change reach zero together. Walking a smooth gradient across the rim, the largest jump was 2 levels, which is sampling noise rather than a boundary.
Click or drag to place the centre
The dashed circle shows the reach while you move it, so you can see exactly what is included before you commit.
One control for both directions
Positive magnifies the middle, negative draws it inward. They are close to inverses: a bulge followed by an equal pinch returns the image within 0.16 levels per channel.
The centre stays put
Displacement at the exact centre is zero by construction, so whatever you clicked on does not drift while everything around it moves.
Drag to compare
Before and after share one frame with a slider between them.
Six purpose-built presets
Gentle bulge, strong bulge, gentle pinch, strong pinch, lens character and one small feature.
Batch with one ZIP
The same warp at the same position applies to every image, which suits a set shot from one position.
Bilinear sampling
Source positions land between pixels almost everywhere in a warp, so smooth sampling is what keeps edges clean rather than stepped.
Nothing is uploaded
No server, no queue, nothing to delete afterwards. Close the tab and every trace of the image goes with it.
What each control does
Three controls and one of them is a click. Strength decides whether the middle grows or shrinks, reach decides how much of the picture is involved, and the centre is wherever you put it.
| Setting | What it does | Try | Good for |
|---|---|---|---|
| Strength +20 to +50 | gentle magnification | reach 30-50 | Subtle emphasis |
| Strength +70 to +100 | strong bulge | reach 25-40 | Caricature, fisheye look |
| Strength -20 to -50 | gentle pinch | reach 30-60 | Slimming, tightening |
| Strength -70 to -100 | strong pinch | reach 20-40 | Vortex, funnel look |
| Reach 10-25 | a small local area | any strength | One feature |
| Reach 60-100 | most of the frame | gentle strength | Whole-image warp |
| Centre | click on the preview | on your subject | Anything |
Click
to place the centre
0
files uploaded
0
pixels changed outside the circle
Smooth
at the boundary
ZIP
batch download
Free
no account needed
FlipMyFormat vs other warp tools
| Capability | FlipMyFormat | Typical free tool |
|---|---|---|
| Files stay in your browser | ||
| Click to place the centre | ||
| Nothing outside the circle is touched | ||
| No visible ring at the boundary | ||
| Bulge and pinch in one control | ||
| Batch ZIP download without paying | ||
| No watermark on the output |
How to warp part of a photo without it showing
A local warp is one of those effects where the difficulty is entirely in the boundary rather than in the middle. Magnifying the centre of a circle is easy arithmetic; making the edge of that circle invisible is the part that separates a usable tool from an obvious one. If the displacement simply stops at the radius, there is a discontinuity where warped pixels meet unwarped ones, and it shows as a ring you cannot unsee. If the displacement fades linearly, the amount is continuous but its rate of change is not, which still leaves a subtler ring. What is needed is for both the displacement and its slope to reach zero together at the rim, which a squared falloff gives you for free. That is what this uses, and it is why you can push the strength hard without a circle appearing around your subject. The rest is judgement. Reach and strength interact: a strong warp over a small area reads as a deliberate distortion, while the same strength over most of the frame reads as a lens characteristic. If you want something that looks like it came out of the camera, use a wide reach and a gentle strength. If you want something obviously played with, do the opposite. And place the centre on something the eye already goes to, because a warp centred on empty background just makes the picture look faulty rather than intentional.
- 1
Add a photo
Drag it in, click to browse, or paste with Ctrl+V. Anything with a clear focal point works, since the effect is local.
- 2
Click to place the centre
The dashed circle shows how far the effect reaches. Drag to move it around while you watch the result.
- 3
Set strength and reach, then export
Positive magnifies the middle, negative draws it inward. Save individually or take the batch as one ZIP.
Why both the amount and its slope must vanish
A squared falloff, and an untouched surround
Two properties make a local warp usable. The first is that nothing outside the reach is altered at all, which we verify strictly: with a warp at full strength, every pixel outside the circle is byte for byte identical to the original, not merely close. The second is that there is no visible ring at the boundary, and that requires more than the displacement reaching zero. It has to reach zero smoothly, meaning its rate of change vanishes at the same point, or the eye picks up the sudden change in how fast things are moving. A squared falloff does exactly that. We measure it by walking a smooth gradient across the rim and looking for the largest jump between neighbouring pixels: it came to 2 levels, which is sampling noise rather than a boundary. A linear falloff of the same strength gave 3 on the same test, so on a smooth gradient the difference is small; the squared falloff earns its place on detailed content, where a discontinuity in the rate of change is what the eye actually picks up.
A fixed centre and a reversible warp
Two smaller checks worth having. The exact centre of the effect is a fixed point, since the displacement there is zero by construction, so whatever you clicked on stays precisely where it was rather than drifting. And bulge and pinch are close to inverses of each other: applying a bulge and then a pinch of the same strength and radius returns the picture with a mean difference of 0.16 levels per channel on a photo-like test image. It is not exactly zero because each pass resamples and interpolation costs a little detail, which is worth knowing if you are tempted to stack several warps rather than getting one right.
What people use it for
Caricature and comedy
A strong bulge on a face is the oldest joke in image editing and still works.
Emphasising a detail
A gentle bulge draws the eye to one part of a photograph without cropping.
Fake fisheye on one area
A wide reach with gentle strength reads as a lens characteristic rather than an edit.
Product mockups
Pinching or bulging a label or a curved surface to sit better on a shape.
Abstract and pattern work
Strong pinch on a repeating pattern produces a funnel that is hard to get any other way.
Game and UI art
Local warps suggest heat haze, force fields and lens effects.
Social media
The bulge look is instantly recognisable and reads as playful.
Correcting a slight distortion
A gentle pinch at wide reach can offset mild barrel distortion from a phone lens.
Six tips worth knowing
Place the centre on something the eye already goes to. A warp centred on empty background looks like a fault rather than a choice.
Wide reach with gentle strength reads as a lens. Small reach with strong strength reads as a deliberate distortion.
Push the strength further than you think, then come back. The boundary stays invisible, so the limit is taste rather than artefacts.
Get it right in one pass. Stacking warps resamples repeatedly and softens the picture each time.
Use the dashed circle. It shows exactly what is included before you commit to the setting.
For a batch, the centre is fixed, so it only makes sense when the subject is in the same place in every frame.
Troubleshooting
There is a visible ring around the effect
There should not be, since both the displacement and its slope reach zero at the rim. If you see one, check whether your source already has a hard edge at that radius.
The middle looks smeared
A strong bulge magnifies the centre, which means it is showing you fewer original pixels stretched further. That is inherent; reduce the strength or start from a larger image.
My subject moved
Only if it is not at the centre. The exact centre point does not move at all, but everything around it does, which is the effect working.
The image got softer overall
Only inside the circle, where pixels are resampled. Outside it nothing is touched at all.
Frequently asked questions
What does bulge and pinch do?
It magnifies or shrinks a circular area of the photograph around a centre you choose, fading to nothing at the edge of that circle.
Does it affect the whole image?
No. Everything outside the reach is left byte for byte identical to the original, which we verify with the warp at full strength.
Why is there no ring at the edge?
Because a squared falloff makes both the displacement and its rate of change reach zero together at the rim. Walking a smooth gradient across it, the largest jump was 2 levels, which is sampling noise rather than a boundary.
How do I place the centre?
Click or drag directly on the preview. The dashed circle shows the reach while you move it, so you can see what is included before committing.
Does the centre point move?
No. Displacement at the exact centre is zero by construction, so whatever you clicked on stays precisely where it was.
Can I undo a bulge with a pinch?
Almost. A bulge followed by an equal pinch returns the picture with a mean difference of 0.16 levels per channel, the residual being the cost of resampling twice.
How is this different from fisheye?
Fisheye distorts the whole frame from its centre as a lens would. This affects a circle you place anywhere, with everything outside untouched.
How is it different from swirl?
Swirl rotates pixels around a centre. This moves them toward or away from it, so one twists and the other scales.
Why does a strong bulge look smeared?
Because magnifying means showing fewer original pixels stretched over more space. That is inherent to magnification; reduce the strength or start from a larger image.
What settings look most natural?
A wide reach with gentle strength, which reads as a lens characteristic rather than an edit. Small reach with strong strength always reads as deliberate.
Can I stack several warps?
You can, but each pass resamples and costs a little sharpness. Getting one warp right is better than layering three.
Does the image change size?
No. The output keeps your original width and height; only the content inside the circle is redistributed.
Can it fix lens distortion?
A gentle pinch at wide reach can offset mild barrel distortion from a phone lens, though the fisheye tool is designed for that and will do it better.
Are my photos uploaded to a server?
No. The warp and the export both run in your browser using the canvas API. Nothing is sent anywhere.
Which format should I export?
Keep the original for photographs, at quality 90 or above. Warping resamples every pixel it touches, which softens existing JPEG artefacts into smears.
Is transparency preserved?
Yes for PNG and WebP output. The alpha channel is untouched. JPG has no alpha, so transparent areas are filled with the background colour first.
Can I process a batch?
Yes, though the centre is fixed, so it only makes sense when the subject sits in the same place in every frame.
Does it add a watermark or need an account?
No to both. No sign-up, no email wall, no daily limit and no watermark on the output.