What is the best way to bulk convert heic to png on my Mac?

Just to add, if all the images are in one folder, select all the images, control click on the selection then choose Quick Actions > Convert Image.

Note that dialabrain's suggestion does not require installing anything. It is already there in your mac - select, control-click, choose Convert Image and confirm.

VikingOSX wrote:

I thought briefly about writing a short Zsh script here to do the HEIC to PNG conversion with sips and bailed on that idea for the handy Convert Image QA.

I had even constructed a find statement that would convert them. Couldn't figure out how to get it to support paths with spaces. Too many quotes being used for other things. Personally, I'd never really use find or even zsh. Why people waste their time not writing Perl scripts, I'll never understand.

find files -iname "*.heic" -exec sh -c 'base=`basename "{}" .heic`; sips -s format png {} --out /tmp/png/$base.png' \;

It's a bit of a catch-22. Quick Action is the clear winner here. But once someone wants just a little bit more than what Apple provides, they pretty much have to code it themselves. Modern Apple don't do no "options".

There are various ways but the easiest - to my mind - is with the inestimable Graphic Converter.

https://www.lemkesoft.de/en/image-editing-slideshow-browser-batch-conversion-metadata-and-more-on-your-mac

Check out pg 22 in the manual.

This free app from the App Store will batch change HEIC to JPG:

It gives you the option of jpeg quality.

There are quite a few apps in the App Store that will also convert. They range from free to $9.99 with more free than non-free.

The following Quick Action Shortcut will prompt the user with a list from which to choose the converted image type. I removed heic, and other formats from this list that did not work. Default is JPG.

The side effect of using this list approach is the loss of the Quality option on the Convert action. I was able to select random RAW images (DNG, RW2, NEF, etc.) and convert to image types from this list. If a RAW format is not supported by Apple, then the conversion will still occur to an image you cannot view in Finder, Quick Look, or Preview. Just tried this with a Nikon Z8 NEF with the preceding predictable result.

Darrinschwartz wrote:

The image size of converted jpg are too big. Anyway to reduce the file size? It is not a good option to be inserted into a web page.

Too big in what way? JPEG files are a relic of another age. They use extreme, lossy compression to have a file size that is as small as possible so that the web looks good on your 9600 baud dial-up modem.

Fast forward to 2023 and what's the point? The CSS files alone on each web page are bigger than the images from 1997. The javascript files are even worse.

And JPEG files are only small on disk or during transfer. Once you open them, they will take up the same amount of RAM as any other image of the same dimensions. Luckily, JPEG files are limited to 65536 pixels or lines in a dimension. I have run into the limit in the past. The JPEG file size was tiny, but I didn't have enough RAM to open the image.

These days, PNGs are a better choice for web images because they support transparency. But you will want to reduce the size of the image to something reasonable. At one point, I had posted a tip on how to use the built-in "sips" tool to convert these files. But the Quick Action is much easier. However, if you want to also resize the dimensions of the images, then you might want to look into using "sips" on the command line.

Beyond bulk conversion, you might consider disabling HEIC on your iPhone so you don't have to deal with it in the future.

BTW, if you are using HEIC with the idea that it gives you better resolution than JPEG, consider using Apple ProRaw instead.

Hadn't tried it on multiple files before. Works well but the max JPEG quality produces an image that's about ½ of what the HEIC Converter does which means there is probably less compression with the 3rd party app. However, the pixel dimensions are the same.

Probably by inserting some action before the convert that pops a user image type selector. Easiest done is in a Run AppleScript with a choose list dialog and then pass that image selection on to the Convert action as a variable to be selected instead of the hardcoded image type (e.g. JPEG). I willl take a closer look at this later as I have some more yard work to do this afternoon before rain.

There are any number of ways to reduce the file size of a JPG - or more technically, to reduce the quality of the file, and so reduce the file size.

For instance: In Preview, open a jpeg file and go File -> Export

Select JPEG from the format menu and see what happens when you use the Quality slider.

etresoft wrote:

JPEG files are a relic of another age.

Since its introduction in 1992, JPEG has been the most widely used image compression standard in the world, and the most widely used digital image format, with several billion JPEG images produced every day as of 2015.

From: https://en.wikipedia.org/wiki/JPEG

Luis Sequeira1 wrote:

The Qyuick Acrion that was mentioned offers different quality options (and thus different file sizes) for jpeg files.

That's not quite accurate. The only options are to change the image dimension, not the level of compression (quality).

dialabrain wrote:

Since its introduction in 1992, JPEG has been the most widely used image compression standard in the world, and the most widely used digital image format, with several billion JPEG images produced every day as of 2015.

And it's an absolute trash of a format. No transparency. Limited dimensions. Funky, limited colourspace. Lossy with horrible artifacts. It is, in all respects, the image format that was made for the web.

Probably the worst thing anyone could do is convert HEIC to JPEG. At least convert it to TIFF or something. That being said, HEIC is nothing to write home about. Anyone want a fun exercise? Start with a high-quality TIFF. See if you can save it in lossless HEIC. 😈

And it's an absolute trash of a format. No transparency. Limited dimensions. Funky, limited colourspace. Lossy with horrible artifacts. It is, in all respects, the image format that was made for the web.

Gee, whatever you do don't tell all those engineers who work for Canon, Nikon, Panasonic, Sony et al who make cameras and are addicted to Jpegs.

:)