Every now and then I find myself in need of converting an image to another format, especially when the application I’m working with does not support the file format I have at hand. Recently I find myself needing to convert several webp formatted files, a format developed by Google as a replacement for PNG, JPEG and GIF. Unfortunately quite a few applications still do not support this new(er) format.
There are a bunch of tools out there that can do this for us, like Pixillion from NCH Software (free version available), or online services like CloudConvert. MacOS however already comes equipped with a suitable tool that can help us with that – and can even handle a batch – called “macOS Preview“.
In this article:
How to convert images, to different file formats, with Preview that comes with macOS – one at a time, or in batch.
As mentioned above, we’d like to convert images to a different file format so we can work with the images in our applications that currently do not support the file format we have at hand.
I’ll illustrate this with “webp” images which I’d like to convert to JPEG or PNG, but basically this can be done with any format supported by the “Preview” application.
Please note that this will work for non-image file formats, like 3D models of MS Office documents, as well – however the result may not always be as great as one would hope for.
Short Version for the impatient …
Open the file, or files, with the macOS Preview application.
When doing a batch: Select all file thumbnails on the right.
From the “File” menu select “Export” (or “Export Selected Images”), select desired file format and click “Save”.
That’s all there is to it …
Free Alternative – Webp Converter (offline)
A free application called “Webp Converter”, which can be found in the Apple App Store (link), offers file conversion both ways between JPG/PNG and WEBP.
This application is available for Windows and MacOS – see Developer website, which also offers online conversion.
These are the formats macOS Preview can read at the time of writing this article. Most of these we can read and therefor convert.
Note : I assume Apple will add support for other formats as new formats emerge and become more commonly used.
Preview Readable File formats
| File Type |
Description |
Extension(s) |
| AI |
Adobe Illustrator artwork files (if PDF content included in file) |
AI |
| BMP |
Windows bitmap files |
BMP |
| CR2 |
Raw image file used by Canon cameras |
CR2 |
| DAE |
Collada 3D files |
DAE |
| DNG |
Adobe Digital negative files |
DNG |
| DOC |
Microsoft Word Files |
DOC, DOCX |
| EPS |
Encapsulated PostScript files |
EPS |
| FAX |
Faxes (TIFF) |
FAX |
| FPX |
FlashPix files |
FPX |
| GIF |
Graphics Interchange Format files |
GIF |
| HDR |
High-dynamic-range image files |
HDR |
| HEIC |
High Efficiency Image File Format |
HEIC |
| ICNS |
Apple Icon Image files |
ICNS |
| ICO |
Windows icon files |
ICO |
| JPEG |
Joint Photographic Experts Group files |
JPG, JPEG |
| JPEG-2000 |
JPEG 2000 files |
JP2, JPG2 |
| KTX |
KTX Software OpenGL/Vulkan Textures and images |
KTX |
| OBJ |
Wavefront 3D files |
OBJ |
| OpenEXR |
OpenEXR files |
EXR |
| PBM |
Netpbm Portable BitMap (black & white) |
PBM |
| PDF |
Portable Document Format version 1.5, with some additional features |
PDF |
| PGM |
Netpbm Portable GrayMap (gray scale) |
PGM |
| PICT |
QuickDraw image files |
PICT, PCT, PIC |
| PNG |
Portable Network Graphics files |
PNG |
| PNTG |
MacPaint Bitmap Graphic files |
PNTG |
| PPM |
Netpbm Portable PixMap (color) |
PPM |
| PPT |
PowerPoint files |
PPT, PPTX |
| PS |
Adobe PostScript files |
PS |
| PSD |
Adobe Photoshop files |
PSD |
| QTIF |
QuickTime image files |
QT, QTIF, MOV |
| RAD |
Radiance 3D Scene Description files |
RAD |
| RAW |
Raw image files |
RAW |
| SGI |
Silicon Graphics Image files |
SGI |
| STL |
STereoLithography 3D format files |
STL |
| TGA |
TARGA image files |
TGA, ICB, VDA, VST |
| TIFF |
Tagged Image File Format files |
TIF, TIFF |
| XBM |
X BitMap files |
XBM |
| XLS |
Microsoft Excel Files |
XLS, XLSX |
At this time, Preview can write the following formats from macOS Preview:
Preview Writable File formats
| File Type |
Description |
Extension(s) |
| JPEG |
Joint Photographic Experts Group files |
JPG, JPEG |
| JPEG-2000 |
JPEG 2000 files |
JP2, JPG2 |
| OpenEXR |
OpenEXR files |
EXR |
| PDF |
Portable Document Format |
PDF |
| PNG |
Portable Network Graphics files |
PNG |
| TIFF |
Tagged Image File Format files |
TIF, TIFF |
Warning – Converting non-images, like documents (Word/Excel/etc) and 3D model files (STL, OBJ, etc) may not produce the best results.
Note – At the time of this writing, Preview does not yet support the much more efficient WebP format for export.
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Convert one Image
To convert a file, we will first need to open it with Preview.
Obviously this can be done in several ways … these are you options:
- Double click the file if Preview is already the default file viewer for this file format.
- Right click the file, and select “Open With” – “Preview” in cases where Preview is not the default viewer.
- Open Preview, and select the file (when Preview gets opened, a file dialog will appear).
- With preview already open, chose from the menu “File” – “Open“.
Open file with Preview
Now that we can see the image or document, we convert it by using the Export functionality of macOS Preview.
This is done by opening the ‘File” menu and selecting the “Export” option.
Preview – Export File as …
Next a file dialog will open:
Preview – Export File Dialog
Here we can enter the filename, and select one of the available formats:
Preview – Available Export Formats
And finally click “Save” …. and this is all there is to it.
Convert a Batch of Images
The same method as described for one image can be used for batch conversion – even with a mix of different source files.
For example, we can convert several different files, for example JPG, WEBP and TIFF mixed, all at once to say PNG files.
The steps are similar: Open all files that you’d like to convert in Preview.
You’ll see on the left-side of the opened image, a list of thumbnail:
Open multiple files with Preview
Now select the first thumbnail by clicking it once with the left mouse button.
To select all files:
Scroll all the way down (either with the scroll wheel function of your mouse, or the slider on the right of the thumbnails), hold SHIFT and select the last thumbnail in the list.
Preview – Multiple files selected
The next step is the same as what we did with a single image: we will need to Export the files.
This is done again by opening the ‘File” menu and selecting the “Export Selected Images” option.
Preview – Export selected images …
Next we will see a file dialog similar to what we have seen when converting a single file, with a few small difference though …
- First of all we will need to click “Options” to get access to selecting a file “Format“.
- The other thing is that we cannot enter a filename for our files – Preview will use the filenames of the original files for this (with a different extension of course).
Finally we click “Save“, and all files will now be saved in the selected format, in the selected directory.
And that is it … 😊
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