Here’s how I do most of my batch resizings and recompressions :)

Those questions come quite often in the comments of my shares, “how can I resize all the images in that hentai manga”, or “the images are ridiculously huge, how do you recompress them?“.

Let’s address that, I’m explaining how I do it

Important: I don’t only do it that way. Actual retouchings are ran with photoshop (here’s how), particular image sets will sometimes require different methods, and on the rare blissful occasion nothing is necessary as the scanlators produced perfect images already. Still, the method I’m giving here should work most of the time.
And I’m certain better methods exist, okay, it’s not a contest

Rather than a wall of text, I’m explaining it in ONE image, I can’t do better

In that image, you’ll see my personal settings and every step I take, with occasional additional explanations.

I use the Xnview Classic program: it can work as both an image viewer, and a very handy mass-transformation tool.

With Xnview, I run both:
– the recompression operations (the width and height don’t change, but we recompress the images so that they take less kilobytes/megabytes on the disk)
– the resizing/shrinking operations (we reduce the image’s height, making it easier to read on a monitor and strongly reducing its kilobytes/megabites size)

Here’s my Xnview Recompression / Resizing Guide.

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(January 2021: this post was updated.)

In the past, to recompress the images, I would use another program, ACDsee. But, around 2018 I think, I eventually gave up on it: there was always a risk to still damage the images unless extra care was taken, I would have to come back to several different kinds of images to make sure I didn’t let damaging processing slip unnoticed… That wasn’t worth it.
With Xnview, the results of image recompressing will yield slightly larger sizes in total in megabytes, but there will be confidence no risk is taken. It’s safer.

Also, I slightly changed the default jpeg compression settings in Xnview, saving hundreds of files to disk will take a few more seconds if you’ve got a dying potato PC, but in exchange there’s stronger confidence the images will look as good as before their recompression.
A few useless options were also ticked off.

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Some personal bonus feedback, if you want to toy around and change the default jpeg compression settings in Xnview, I recommend you choose, for your before/after comparisons, an image with reddish surfaces, fading into other colours on the edges, and in deep reds in the center.
Again, it’s just personal experience (AKA: maybe it’s just me, it’s a P sample size of 1), but I noticed it’s those kinds of images that show the more easily when the compression has been too strong and there’s been damage.
… Look, I’m all for saving space by recompressing uselessly big images, but NOT at the cost of damaging image quality.
Would you really want to keep damaged hentai pics on your disk, just to save 30 megabytes, while at the same time you download gigabytes of porn torrents elsewhere on your disk? It’s not worth it, please preserve image quality ^^

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And if I want to rename files?
In Xnview, do Control-A to select all the images, and then F2. Remember the # symbol will be the incremental numbers, start with ## if there are less than 100 pictures (get the idea?), the rest should come easily.

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While I’m at it, I’ll have to update this post with fresher information, but, hey, I once wrote a post about the best friends of the hentai fan…