Photoshop Scripting HELP! Basic resizing is losing quality and wracking my brain!

[Chester24394912jtcm]

I am using Photoshop 2020, on a windows 10 machine.

I have searched all sorts of photoshop scripting websites and I cannot seem to find a solution that works. I have a large image (6480x6480 pixels). In photoshop I can manually resize it to 648x648 and the details look well preserved (the 'diamonds' inside the letter T). BUT, when I try to resize using a script, I lose key details, where my 'diamonds' are now blurred out to what looks more like 'chrome'.  fyi: The PSD file is file that applies a text effect (in this case, diamonds) to the inside of whatever you set your text string to be.

If I take my origianl 6480x6480 psd file and zoom till it is down to 10%, I can still see the jewelled diamond detail.

The script line I use to resize is:

app.documents[0].resizeImage (648, 648, 300, ResampleMethod.BICUBICSHARPER);

Even before I save the image as JPEG or PNG, you can already see the detail is lost even though I keep the resolution at 300 pixel/inch!  

--- prior to the code line above, I initially tried this --

app.preferences.rulerUnits = Units.PIXELS; // use pixels

var sfw = new ExportOptionsSaveForWeb();
sfw.format = SaveDocumentType.PNG;
sfw.PNG8 = false; // use PNG-24
sfw.transparency = true;

 // a bunch of code that successfully save the full size image and PNG files with NO LOSSES

app.documents[0].layers.getByName("Watermark").visible = true;
app.documents[0].layers.getByName("Background").visible = true;
app.documents[0].resizeImage(600, 600, null, ResampleMethod.BICUBICSHARPER); // width, height
var destFileName = "Blog6006Black.png";
app.documents[0].exportDocument(new File(destFolder + "/" + destFileName), ExportType.SAVEFORWEB, sfw);

... at this point I think I would even be happy with a script that does just a screenshot of my original large file as it appears inside photoshop 

[Stephen Marsh]

@Chester24394912jtcm 

I doubt that the following AM function will result in anything different, however, it is worth a shot:

imageSize(648, 648, "bicubicSharper");

function imageSize(width, height, resampleMethod) {
	function s2t(s) {
        return app.stringIDToTypeID(s);
    }
	var descriptor = new ActionDescriptor();
	descriptor.putUnitDouble( s2t( "width" ), s2t( "pixelsUnit" ), width );
	descriptor.putUnitDouble( s2t( "height" ), s2t( "pixelsUnit" ), height );
	descriptor.putEnumerated( s2t( "interfaceIconFrameDimmed" ), s2t( "interpolationType" ), s2t( resampleMethod ));
	executeAction( s2t( "imageSize" ), descriptor, DialogModes.NO );
}

[Chester24394912jtcm]

Thanks for you effort.  I tried it out, but still got the 'chrome' effect.   

I have literally spent 6 hours on this.  It should be dead simple, but it's not (at least for me)

[Stephen Marsh]

It is a huge reduction in size, my expectation wouldn't be the same level of detail. 

Can you crop out a relevant section of the high res image for experimentation?

[Chester24394912jtcm]

See  my response to r-bin below.  My current work-around is to export a 6480x6480 PNG file, have my script read in the PNG, resize it, and spit it out as a PNG. The work-around works (I get good detail in the shrunk down 648x648 PNG file), but I am sure it adds a bit of time to a script that already takes 1 minute 40 seconds to run.

[r-bin]

If you are using layer effects, then try in the code from Stephen_A_Marsh add the line: descriptor.putBoolean(stringIDToTypeID("scaleStyles"), true);

[Chester24394912jtcm]

that extra line made the final result a tiny bit better but still no real detail. 

The detailed image is a screenshot from a PNG file generated from a PSD files that has a file link to the original large PSD and it seems to look fine at an image height of 1624. I could try this at a smaller size, but I find refreshing links SLOW.   The other image is when resizing the original large PSD file down to 648x648 using the extra line of code you recommended.

[r-bin · Accepted solution]

Flatten the image before resizing.

Then resize using this method: "deepUpscale"  instead of "bicubicSharper".

Also for a flat image, try this plugin to reduce the size - https://pm.vogu35.ru/~c3c/plug-ins/c3cimagesize.htm

[Stephen Marsh]

@r-bin - thanks, my test layer didn't contain any effects so I obviously missed that.