Image optimisation software (batch) recommendations?

[Paul_N]

I've completed a mammoth conversion of FrameMaker documents into Flare. The output was PDF from FrameMaker and it's now HTML5 from Flare. It generated over 2000 web-safe images in jpg and png format.

I've noticed that some of the images are much bigger than they need to be. E.g. a png that was 700kb was opened and saved at 50kb (I'm guessing there was little or no compression), without changing its size or resolution! The before and after images were indistinguishable.

I want to get the Flare output size down by optimising the images size without compromising quality. But I can't practically optimise each image individually, not with thousands in the output.

So, can anyone recommend batch image optimisation software, preferably one that I can install locally on my PC ? Something that I can point at the images folder and get it to churn through them and optimise their size in kb?

[trent the thief]

Hi Paul,

I have no specific package for that purpose. I'm using GIMP to do everything except organize images.

If you know exactly what you want to do to the images, make it a macro in GIMP and then you can use the BIMP plugin to perform batch macro operations on full directories. I've used BIMP for many things. Most recently converting a batch of white-on-black terminal screen shots. I inverted the colors (white-on-black to black-on-white), added a border, and exported the modified images.

GIMP and BIMP are pretty easy to use.

Edit: XnView MP can also do batch operations, but I haven't used that feature. (https://www.xnview[DOT]com)

[SteveS]

Snagit has batch processing capabilities.

You can select images in File Explorer, right click and select Snagit -> Batch convert images. You can also select a folder and Snagit will identify images it can process, including those in sub-folders.

In step 2 of the batch export dialog select Image Scaling -> Resize image...

Then select Scale to width (or height) and select a suitable size. 600 pixels works for most images. Make sure you select use smooth scaling and keep aspect ratio before clicking OK.

[andrewb]

My team uses a great tool for PNG files called PNGGauntlet (https://pnggauntlet.com/). It handles batch optimization really well. It will also convert other formats to PNG.

[Paul_N]

Thanks for the responses all, I'll check out the recommended tools.

[Paul_N]

I thought I'd update this topic: The tool that worked best is called Mass Image Compressor. On a trial run it reduced a 300Mb image library of mostly png's down to 100Mb. The canvas size was always untouched, and it reduced image size by reducing colour bits and resolution - there were many 4 or 8 bit colour images set to 16 bit, and 300dpi when 96dpi will do. There was no noticeable difference in quality on a monitor for our HTML help.

The only downside is that it's not been updated since 2016 as far as I can tell. This may cause issues on corporate network's security scans these days.

[trent the thief]

If you're comfortable using GIMP, installing the BIMP batch plugin and compressing them in GIMP is an option. I had great success inverting screen colors of about 200 white on black terminal screen shots to make them more readable and to not eat so much toner.

https://alessandrofrancesconi.it/projects/bimp/

[trent the thief]

If you're comfortable using GIMP, installing the BIMP batch plugin and compressing them in GIMP is an option. I had great success inverting screen colors of about 200 white on black terminal screen shots to make them more readable and to not eat so much toner.

https://alessandrofrancesconi.it/projects/bimp/

[NorthEast]

IrfanView has a good batch converter too: https://www.irfanview.com/
It's not pretty, but it's surprisingly good for image file processing and gets regular updates.

[AlexFox]

I highly recommend PowerToys - it's a Microsoft-published set of utility tools with some fantastic features, one of them being batch image resizing in a directory.

[trent the thief]

Hey, thanks Alex! I'd not seen those before that I can remember. Those are some great apps.

[SteveS]

Powertoys also has an OCR image capture tool; you can take a screenshot of a page of text (such as a protected web page) and save it as text.