How to batch convert and keep original file size?

[chimchar311]

Been trying to convert some of my .jpeg images and add a date stamp to it, but everytime I do it the size reduces by 50%. I have tried the Transform Resize action and kept the preset to original but it still reduces the file size quite considerably. Anyway we can keep the file size whilst just adding a date stamp on top?

[cday]

On the Output tab, at right, Settings... > Use estimated quality (when possible) ...

[chimchar311]

On the Output tab, at right, Settings... > Use estimated quality (when possible) ...

much appreciated, works well!! although the size has actually increased by 18% - is this a side effect of enabling that setting?

[cday]

... much appreciated, works well!! although the size has actually increased by 18% - is this a side effect of enabling that setting?

I'm not sure, possibly one of the other settings options has been changed?