Flip BMP

How to Flip a BMP Image Online

1. Choose Your BMP Files: Drag and drop BMP images onto the page or click "Choose BMP files" — up to 50 at once. The first photo opens in the editor and the rest line up as thumbnails below it; with two or more photos open, "Add more" adds files to the same batch.
2. Flip It: In Flip, click "Horizontal" for a mirror image or "Vertical" to turn it upside down; click again to undo it. Flips stack with rotate, and the flip applies to every photo in the batch.
3. Pick the Output Format (Optional): "Save as" keeps "Same as original" or saves as JPG, PNG, WebP or another format. For JPG, WebP and AVIF output, the "Quality" slider (40–100) trades file size against detail. Resize, Crop, Rotate and Flip all work in the same session, and "Undo" steps back.
4. Download: Click the Download button, which names the output format (for example "Download PNG"), for one photo, or "Download all (.zip)" for a batch — "Download one by one" saves the files separately. BMP files are processed right in your browser, so they are not uploaded. No sign-up, no watermark.

Why Flip a BMP?

BMP (Windows Bitmap) is Microsoft's native raster format, dating back to the BITMAPCOREHEADER in Windows 2.0 / OS/2 1.x and standardised with the BITMAPINFOHEADER in Windows 3.1x. It is uncompressed by default (optional RLE for indexed images), supports 1, 4, 8, 16, 24, and 32 bits per pixel, and stores scanlines bottom-up unless the height field is negative. That bottom-up convention is exactly why so many BMPs come out vertically inverted from non-Windows toolchains — vertical flip is the fix.

• Correct mirrored scanner output — Many flatbed scanners and document cameras mirror the source when documents are loaded face-down or the optical path uses an internal prism. A horizontal flip restores the original reading direction.
• Fix vertically inverted captures — Embedded systems, microscope cameras, and frame grabbers that write raw .bmp frames frequently emit top-down rows that downstream Windows viewers interpret as bottom-up, producing an upside-down image. A vertical flip realigns it.
• Industrial machine vision — Cognex, Keyence, and Basler line-scan cameras still ship sample BMPs; flipping is part of the calibration step when the sensor is mounted upside-down or the conveyor runs the opposite direction.
• Iron-on transfers and screen printing — Heat-transfer paper and silkscreen positives have to be horizontally mirrored before printing so the design reads correctly once flipped onto the substrate. BMP is still the lingua franca for older Roland and Epson DTG drivers.
• Legacy Windows app assets — Visual Basic 6, MFC dialogs, and ancient game sprite sheets ship as BMP. Designers flipping enemy sprites or button states keep the format intact rather than re-saving as PNG.
• Mirrored variants for design layouts — A symmetrical book cover or product mockup often needs a left-and-right pair from a single source asset.

BMP vs Modern Alternatives — Format Comparison

BMP Flip Settings — What the Editor Offers

The editor has no DPI, bit-depth, compression-type or file-size-target setting. To hit a byte budget, run the result through Compress BMP.

Frequently Asked Questions

Does flipping a BMP lose any quality?

Not for an ordinary 24-bit BMP. Flipping is a pure pixel rearrangement — Microsoft's own IWICBitmapFlipRotator describes the operation as a coordinate transform along an axis, with no resampling involved — and the result is written as an uncompressed 24-bit BMP. Two things do change: a 1-, 4-, 8- or 16-bit BMP is saved as 24-bit (same picture, larger file), and a 32-bit BMP with transparency is flattened onto white. The "Quality" slider only matters if you save as JPG, WebP or AVIF.

Why does my BMP open upside-down in some viewers but right-side-up in others?

BMP scanlines are stored bottom-up by default; the format also allows top-down ordering by writing a negative biHeight in the header. Tools that ignore the sign assume bottom-up and render top-down BMPs inverted. Apply a vertical flip and re-save to normalise the orientation.

Should I flip horizontally or vertically for an iron-on transfer?

Horizontally. Heat-transfer paper, sublimation transfers, and most screen-printing positives need a left-to-right mirror so the design reads correctly once the paper is flipped onto fabric. Vertical flip is for upside-down captures, not transfers.

Will the output also be a BMP, or do I have to keep the format?

With "Save as" left on "Same as original" the output stays a .bmp. If you'd rather move to a smaller modern format, pick PNG (lossless) or JPG (photographic content) in "Save as" before you download — or use BMP to PNG or BMP to JPG — typical 24-bit 1080p shrinks from ~6 MB to ~1–3 MB (PNG) or ~200–500 KB (JPG).

Can I flip a 1-bit (black-and-white) or indexed BMP without breaking the palette?

The picture flips cleanly, but the colour table does not survive: a BMP edited in your browser is redrawn in 8-bit-per-channel colour, so a 1-bit fax-style BMP, an 8-bit indexed sprite sheet or a 256-colour icon is saved as a full-colour BMP of the same picture. Save as PNG with "Save as" if size matters, or flip indexed BMPs in a tool that keeps the palette for legacy hardware.

Does this also work for .dib files or BMPs without the .bmp extension?

Files genuinely in the BMP/DIB container will work if you rename them to .bmp first. The container is detected by the BM magic bytes at offset 0, not by the extension. Truly legacy .dib device-independent bitmaps with the older BITMAPCOREHEADER are also accepted.

Can I flip and crop or rotate in the same step?

Yes. The same editor has Resize, Crop and Rotate tabs next to Flip, so you can flip, then crop or turn the picture before one download (Crop BMP and Rotate BMP open the same editor on those tabs). Flips and 90° turns move pixels without resampling; a fine-angle rotation does resample.

What happens to the transparency in a 32-bit BMP?

32-bit BMPs technically support an alpha channel via BI_BITFIELDS, but many legacy Windows viewers ignore it and render the alpha as opaque black. This editor does not write BMP alpha at all: a BMP it saves is 24-bit, with transparent areas flattened onto white. To keep the transparency, pick PNG in "Save as" (or use BMP to PNG).

Can I flip multiple BMP files in batch?

Yes — drop up to 50 BMP files at once (a mixed batch works too). The flip direction you set applies to every file in the batch; "Download all (.zip)" saves every flipped result in one ZIP, or use "Download one by one" to save them separately.