How to enable functionality only for specific image component, not all

You are on the right path. Yes, you have to create a new component for that but you can't override the Image component type otherwise, as you have seen, all the images will get that.

What makes those images unique? How could you differentiate between a regular image and a specific image? That logic you will need to add to your isComponent fn.

Tip: Extends your new component type from the existing Image component type.

I tried this and removed gjs-data-type="image" from the img tag where i want the functionality to be applied. But, neither does it implement the functionality on it and but also messes with the rest of component properties.

domc.addType("image", {
    model: defaultModel.extend({
      defaults: Object.assign({}, defaultModel.prototype.defaults, {
        initToolbar() {
          typeImage.prototype.initToolbar.apply(this, arguments);
          const tb = this.get("toolbar");
          const tbExists = tb.some(item => item.command === "open-assets");

          if (!tbExists) {
            tb.unshift({
              command: "open-assets",
              label: toolbarIcon
            });
            this.set("toolbar", tb);
          }
        }
      }),
      isComponent: function(el) {
        if (el.tagName == "IMG" && /logo.png/.test(el.src)) {
          return { type: "image", src: el.src };
        }
      }
    })
  });

@sakshigarg9 to prevent messes use the new addType (in your case you miss the view property and this breaks stuff in the old declaration)

BTW I suggest to create a NEW component type by extending the image instead of just extending the current one (in this way you're editing all images)