"1. It's too dark/light/small etc.
2. That sensor dirt shows up horribly on the monitor in the Picture viewer and you wish you could clone it out and repost."
Read the solution in the post below. Help is at hand! It even works with images you have already shared that are in your Lightroom catalogue!
Reshared post from +Ellie Kennard
Tutorial – Using Lightroom and the Picasaweb Plugin – a Twist and a More Powerful Control for your Google+ Images
Do you use Lightroom to prepare images to post to G+? If you do, this tutorial will explain how, using's awesome plugin Picasaweb for Lightroom, you can take even more control of the images you have posted – after they are uploaded . It is possible that you already use this plugin. But you might not be aware of one powerful feature it has.
You know how frustrating it is when you upload an image to G+ (by exporting a jpg from LR and then adding it to an album on G+) and suddenly you realize that:
1. It's too dark/light/small etc.
2. That sensor dirt shows up horribly on the monitor in the Picture viewer and you wish you could clone it out and repost.
This usually happens about 10 seconds after posting, but 5 seconds after the first plus ones or comments appear. So you don't want to delete this image, correct it and reupload or you will lose those early interactions. What you would like is simply to upload over the top of that one, overwriting it with the changes, keeping all of the comments and +1s that are flooding in!
Up to now, uploading directly via the plugin meant that you had that full control I mention above. But it also meant that you have to share an album, which gives those thumbnails down the side of the image in your posting and your full image is not seen in the posting as you might like. What you want is for your share to have a large view of the beautiful photograph you have prepared. That image alone.
This tutorial shows you how you can do the same thing, with just a few extra steps, sharing what looks like a single image in all its glory, with no album thumbnails down the side, but an image which is in the album, so viewers can browse through other images after viewing the posted one. And if you find that you need to edit the image in any way, you can re-upload by overwriting that posted image, keeping all info intact. (and any comments will also be downloaded into your Lightroom catalogue, connected to that image, too.)
There is a series of slides in this tutorial, some perhaps a little basic, with the full explanation for each slide in the description. I hope it helps give you a more powerful control over your uploaded images and a more impressive share of an image in an album.