Cloud-AI provider image size is too large

[gibbotronic]

When using a cloud provider for LLM processing of photos, some can fail with image size errors. Eg. with Anthropic Haiku 3.5, I got:
image exceeds 5 MB maximum: 5607404 bytes > 5242880

As the image is base64-encoded, the base64 is 33% larger than the source image. Eg. a 5MB JPG will produce a 6.65MB base64 content that is sent to Anthropic / the LLM provider.

So we actually need to resize the JPG preview we are sending to be 33% smaller than 5MB, therefore 3.76MB or smaller.

I fixed this by running ImageMagick to pass the -define jpeg:extent=3932160 (which is actually 3.75MB) in ai-pp3/dist/file-operations/file-handlers.js:
At the top:

import fsp from "node:fs/promises";

then

export async function createPreviewImage({ inputPath, previewPath, basePP3Path, quality, format = "jpeg", verbose, }) {
    try {
        await (basePP3Path
            ? convertDngToImageWithPP3({
                input: inputPath,
                output: previewPath,
                pp3Path: basePP3Path,
                format,
                quality,
            })
            : convertDngToImage({
                input: inputPath,
                output: previewPath,
                format,
                quality,
            }));
        const tempPath = path.join(
          path.dirname(previewPath),
          `temp_${path.basename(previewPath)}`
        );
        await spawn('magick', [
          previewPath,
          "-strip",
          "-interlace", "Plane",
          "-sampling-factor", "4:2:0",
          '-define', 'jpeg:extent=3932160',
          tempPath
        ]);
        const stats = await fsp.stat(tempPath);
        if (stats.size > 3932160) {
          await spawn("magick", [
            previewPath,
            "-resize", "2000x2000>",        // shrink if too big (keeps aspect)
            "-strip",
            "-interlace", "Plane",
            "-sampling-factor", "4:2:0",
            "-quality", "75",
            tempPath
          ]);
        }
        if (verbose) {
          console.log(`Preview file created at ${tempPath}`);
        }
        await fsp.rename(tempPath, previewPath);
        if (verbose) {
          console.log(`Preview file renamed from ${tempPath} to ${previewPath}`);
          console.log(`Preview file created at ${previewPath}`);
        }
        return true;
    }
    catch (error) {
        if (error instanceof Error)
            throw error;
        throw new Error("Unknown error creating preview image");
    }
}

You can probably think of a better way of resizing the JPG to be 3.75MB in node.js but for now that's what I ran (ImageMagick) because it seemed to be able to resize to a target MB size already easily enough.