Bulk edit, resize, watermark, enhance photos on Apple Mac

If you are a photographer, have a website or work with photos a lot in some other way, here is an excellent Mac tool to bulk edit images. Resize them, enhance them, add filters and more.

There are some great photo editor apps for the Apple Mac, but few of them enable you to process multiple images at once. Mostly, photo editors are designed for working with one or two images at a time.

A photographer may need to provide dozens of photos to a client so they can view them, pick the ones they want and so on. You would not send original raw images and instead you would send low resolution copies. Bulk resizing multiple photos saves time and effort.

A website may include up to a dozen photos in a long post and they need to be a certain size, such as a specific width, not the originals straight off the camera. Raw photos are far too large for web pages, so bulk resizing to a certain width or optimizing them solves the problem.

Collections of photos may exhibit a certain flaw, such as being taken on a dull day and may need the color, contrast and exposure enhancing. It can be tedious work fixing each photo one at a time and bulk editing avoids a lot of effort.

There are many uses for a bulk photo editor and Realmac Software’s Squash is a great utility for macOS. There is a free version and a full version costing $39.99. I use the free version here and it does a lot more than you might expect and most features are fully functional, with just three features held back for paying Pro users.

Add photos to Squash

Open Squash, open a Finder window and a number of photos can be dragged and dropped on the app to add them. A folder can be dropped on Squash to add all the images it contains, which is useful.

Realmac Software Squash bulk image processing utility for Apple Mac
Squash showing image thumbnails and image tools

The app displays all the photos as fairly large thumbnail images and the number shown depends on the window size. Make it larger and more thumbnails are shown. The screenshot above shows the smallest window size with 2×2 thumbnails, but make it full screen and it could show 20, 30 or more.

Bulk resize photos

Resizing a photo in RealMac Software Squash utility for Apple Mac
Make all images a certain size

If you need to output images at a particular size, the Resize module on the right enables you to set a width, height or percentage. You could make all images 800 pixels wide for example. A free size option enables you to specify both the width and height. Setting a specific width is useful if you are preparing images for a website.

Bulk enhance and correct photos

Images often need enhancements specific to each one, but if you have a collection of photos that you want all changed to sepia, black and white, or sharpened for example, Squash can do it, but the paid Pro version of the app is required. This is one of the three features not in the free version.

Bulk enhancing photos with RealMac Software Squash for Apple Mac
Make adjustments and enhancements to photos

Usually, you will apply all effects to all images and output the lot with the same enhancements, but it is possible to output a single image by Ctrl+clicking it if one needs some specific enhancements.

Bulk apply photo filters

The Effects module on the right is used to apply filters to the images. The selected filter is applied to all images that are loaded and you cannot apply different filters to different images. The idea is that you can turn a whole collection of photos into black and white or sepia or whatever filter you want in one go.

Realmac Software Squash bulk image processing utility for Apple Mac
Add filter effects to photos, see before and after applying

Clicking an image makes it fill the window so you can see a larger version and also there is a split view, which shows before and after applying the filter. There are eight free filters and extra filter packs can be purchased

Add a watermark

Image theft is common on the web and people take photos from sites and use them on their own site or may even try to sell them. Adding watermark text to the image helps to deter people from stealing your photos. This is one of the three paid Pro features.

Bulk add watermarks to photos with Realmac Software Squash
There are many settings for adding watermarks to photos

Any text you want can be added to an image and the size and position can be set, the foreground and background colors can be selected, transparency set, font selected and so on. There are plenty of options available for watermark text.

Bulk compress and convert images

The output file format for the images can be selected from JPEG, PNG, TIFF, WebP and AVIF. The first three file formats are well known. Support for WebP has just been incorporated into WordPress and WebP images are more compact at the same quality than JPEG, which means your site will be faster with them. If you have a site, you should be using it and images can be bulk converted to WebP using Squash.

Realmac Software Squash bulk image processing utility for Apple Mac
Bulk convert images from one format to another

Some image formats, like JPEG, WebP and AVIF support compression and there is the usual trade-off between quality and file size. The amount of compression is set using a simple slider and the image has an overlay in the top right corner that shows the resulting file size.

The AVIF format is said to be the best, but it has patchy support at the moment and not all software and web browsers support it. They probably will eventually, but for now WebP is the best image format and Squash is one of the few bulk conversion tools available. It is worth getting it for this feature alone if you have a website.

More bulk editing features

The JPEG file format supports metadata like the GPS location a photo was taken, the camera model and other information. Squash can remove it, which is useful for images shared on the web on your own site or in photo libraries. Some file formats, like WebP, do not allow metadata anyway.

Photos straight from the camera or phone have non-descriptive numberical or date filenames which tell you nothing about the subject. Finder is pretty good at bulk renaming files, but Squash also enables you to rename them as they are output. It’s another paid Pro feature. A prefix, suffix or complete replacement can be specified and numbers are added to the filenames automatically.

Images can be output with the current time and date or the original date created or modified can be kept. It is up to you.

Export photos

When you are happy with the settings for the photos, they can all be output and saved. You can choose the folder they are saved to, but there is also an option to always use a specific folder. A bit like the way browser downloads are always saved to the Downloads folder, you can specify that processed images are always saved to whatever folder you want to use.

A single photo can be saved by Ctrl+clicking it and this is useful if a photo needs different settings to the rest.

Create and use presets

As you bulk process multiple photos, you may find that you repeat many actions, such as setting a certain width, converting to a particular file format, applying a certain amount of compression, applying a specific filter, and so on. All the settings can be saved as a preset and presets are shown in a panel on the left.

Realmac Software Squash bulk image processing utility for Apple Mac
Apply preset settings to a collection of photos

Several presets containing common settings can be saved and you can simply load a collection of photos, Ctrl+click a preset and output the lot using those settings. It is easy and quick and saves you having to configure everything every time.

A collection of photos could be output several times with different presets. You can also Ctrl+click a single photo and choose a preset to save that one image with it. Presets are another useful time saver.


Realmac Software Squash is a useful free utility for anyone that processes multiple photos, applying compression, converting to a particular file format, adding filters and so on. It is recommended for website owners and photographers. There are only three locked features in the free version, but two are good ones and you may consider that image enhancement and watermarks are worth paying for.

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