Good to know... that there are more options... and forum-members that can support me.
As it is now, It works excellent and makes my use simpler and straightforward.
Shortcut key combos have been trimmed so now I use these, simple and handy combinations:
1: ctrl pagedown runs both macro (via tiny twoline macro) 
2: alt opt pagedown runs the trimmed by... macro
3: cmd pagedown runs the new size macro
GreyT
Update on using the 2 "tiffle" macros.
Using them gives me substantial benefits while working with my rather large Scrivener Projects.
It is quite natural now, to select and treat any picture in the document, knowing the digital size will be reduced, and keeping the final visual size (I have settled for 505 in with).
To get some facts on size-reductions, I used a project from 2022, which as such is in fixed number of documents:
Projectsize: 14.640 MB (before)... 14.300 MB (after)
Number of all documents: 3.665
Number of "tiffled" documents: 166
This gives a reduction of about 48% for the 166, and about 2% for the whole project.
so now it is indeed time for 
to tiffle 
Thanks for your help
GreyT
You're welcome - but the real thanks should go to Keyboard Maestro. I don't know about you but KM's done a lot for me:
Oh - BTW - thanks for the
Ohh. I'm just a young greenhorn, compared to you:
But anyway, I guess I have saved tons of clicks, and without KM I could NOT have ventured into these 'facts gatherings', I run now.
And it is interesting, for me, to overcome (to a certain degree 
) my resitance to try something new, in this respect, rather than simply mimicing mouseclicks in my macros 
one of the sideeffects are that some projects now are slimming by a factor of 50%. (the tiffle effect)This is very fine, when talking 25 GB+
GreyT
My curiosity got the better of me about Time saved: ... but I have not found out how this is calculated!!!
I mean 42 days... compared to 126 years 
GreyT
Yes - ridiculous This is what Peter says:
My guess is you can easily double it with a couple of these:
Jiminy
Eating the elephant, slice by sclice
To better/really quantify the benefit (for me) on using the two macros, I have taken a live, 2023 project, and startet to run every document thought the steps.
Frankly I am amazed...
Before the 'live' project contained 1.538 documents (7.720 pages) and 4.75 GB
Now, at about 60% of documents done the numbers are:
1.558 documents (7.776 pages) and ONLY 2.85 GB. 
To check in between I used Finder to peek into the project package, searching for content.rtf and can only marvel over the "Shrinkage" of the larger documents, having (many) photos of say 2048 1536 pix, and the document slimmed down from 50MB to 5MB.
It is delightful for me to know, that when I run the 2 macros, now, all info is preserved... and disk space / time to search/process/save is being optimized
GreyT
Blimey!
Are these all Scrivener documents? If they are you might want to tell your story on the Literature & Latte forum and mention what a good combination Scrivener and Keyboard Maestro make 
Whether or not you do that, it’s brilliant you’re seeing the benefit of them rolling in!
Great stuff 
On the homerun now, just 98 documents to go, in this "Live project". I must take a break for eyes as well as fingers, but the end result is looking marvelous:
Before: 1.538 documents (7.720 pages) and 4.75 GB
Now: 1.580 documents (7.849 pages) and 2.45 GB
And all information, text and visuals are maintained.
Have also adjusted hotkeys to a very useful fingerfriendly dance:
where the last one is entering the message "Foto-Trimmed" into the metadata field "Event Arc", why? Well because this is my sort criteria, for this exercise
Later I'll post my findings in the Scrivener forum as you suggested.
Done...
1.582 documents (7.856 pages) and 2.41 GB
KM Rocks
Many clicks later, I have a question to you:
is it possible to "ignore mouse-movements" while the combined macro is running?
just a tiny movement, like moving the mouse simply to make room for my 
, will offset the pointer somewhat, and that will goof the insertion point for the text: "Trimmed by macro..." ???
When it happens it requires me to do a number of cmd Z to 'undo'
GreyT
I'm afraid not 
Hello - I’m very late to this discussion but maybe I can give some advice here, too …
Palle (@Palle_GreyT) what @tiffle just said on this is absolutely right … you can’t get KM to ignore any input like mouse movements - but there are two options you have
One is an application that blocks all peripheral devices and only listens to one specific shortcut for bringing everything up to usability again by pressing this one shortcut …. I am not going to tell you which one because there are many of them out there and I forgot about their names … 
Another is a complex workaround with asynchronous loops of read store and recall stored mouse positions during the whole work that KM is doing for you since km would have to know what exactly happened to the mouse to catch up on mouse movements you did during the whole process… but that would be very much work to do for you ….
And by the way … love this discussion here … learned a lot about resizing images with KMs native actions just from this topic …
Greetings from Germany 
Tobias
Hi @Nr.5-need_input
thanks for your input... the unintended mouse action is really a result of "slow macro combination"... that is, when I started with the original from @tiffle it worked fine with the delayvalues he suggested, then in some instance (probably schrinking very large images took a bit longer and the macro failed...) so I increased the delayvalue, and not being so patient I did it for all delays, thus the macro got slow(ish) and then I moved the mouse when I thought is should be ready 
...
So maybe I will simply add a spoken text, at the start like this: "Keep OFF the mouse... SpeedyGonzales"
Ah okay I got it … there is another thing you can do … call an asynchronous loop of just showing and hiding a Palette with one macro that has this sentence as name … the macro self doesn’t need any actions …
And let the macro end the loop when the work is done …. If you give the palette the right size and color it should be a nice indicator for a running process because it blinks on your screen all the time until the end. There is a discussion about this on this forum already… but I don’t remember the name of the topic currently…
This could also be a help for you I think 
Greetings from Germany
Tobias
It seems that the booming voice advising me to keep off the mouse helps my twitching fingers ... on that "I'll rest my case" (pun intended)
GreyT
I will... later... until then it wil have to Wait
As my final input, I have moved the Spoken words to the end of the macro: "Mouse is free"... in this way the 'waiting' comes naturaly and not depending on where my eyes may roam...
GreyT