I upgraded my Photoshop action to version 3. This time I focused on making pictures more crisp and adding more light. I love the result. Even the nighttime pictures are better now.
Oh thank you ;3; I find my night time pictures always look bad too! Since I am extremely lazy and impatience, I don’t really like to edit my pictures one by one. But those pictures taken at night time are exceptions. Well, I don’t think I’ve found a perfect solution, but this is what I do.

Hope it helped. I’ve been still finding a better solution for night time screenshots. So if anyone knows better tips, please share them!

While waiting for my object files (848 items in total!) to be merged into a single file, I finally decided to put my action script up for download, knowing there are few people who use my previous action script.
As usual, it’s nothing special at all. What it basically does is to lighten and sharpen images as shown in the preview. Unlike the previous version, this action file was made based on the Lighting Tweak (balanced) and Dynamic shadows. So, if you don’t use these mods, this action might be useless. However, personally I’ve noticed that removing weather files and using the mods instead has improved my graphic a lot.
So, there are two major changes from the previous version: (1) Although recently I haven’t used this tool much, I’ve lowered vibrance and saturation numbers. Because with the lighting tweak, everything is already too much yellowish especially at dusk. The 40-15 one was supposed to be applied on daytime screenshots. (2) I changed the numbers for Unsharp Mark so it can make pictures more clearer.
Tip: You can edit as many photos as you want WITH ONE CLICK by using Batch Process.
This is how I edit 100+ screenshots with one click. As I’m no Photoshop expert, this ‘tip’ is nothing special or fancy, just as my action file itself. But, as this method always pleases my laziness and impatience, I want to share it here C:
Oh, and speaking of action, I updated the action file I uploaded before so there are options for resizing and saving. I use Photoshop CS5. So, if you use different version the Batch window might look different, but you get the idea how to use it. And don’t forget, there are thousands of better tutorials on YouTube or somewhere like that.

1. File > Automate > Batch to open the batch window shown the picture above.
2-1. Select the set and action you are going to use. The screenshot means my action called Twinbrook is stored under OhMySims set. MAKE SURE your action has saving step in it, or your destination folder will be empty.
2-2. Select the folder that your original files are stored. I simply chose the default Sims3 screenshot folder.
2-3. Select the destination folder that your edited pictures are going to be stored. DO NOT use the same folder as you selected in the step 2-2. You might lose your original screenshots as the batch overwrites files.
2-4. Select how the file names are supposed to be. I set like above to keep the original file numbering that the game generates.
3. Click OK and then wait for a few minutes :)
As per requested, I share the photoshop action I use. However this is really nothing special - as seen on the preview, what this action does is no more than making screenshots clear and brighter. I even use factory preset values for curves.
NOTE: (1) I updated this action to include resizing and saving steps. If you don’t want them, you can bypass them by unchecking the radio button before running this action. (2) Vibrance tool is only available for CS4 or above.

You can edit as many photos as you want WITH ONE CLICK by using Batch Process.
Personally vintage coloring or special filters are not my taste, so the only thing I do for coloring is to use the Vibrance tool. In addition, I use curve tool and unsharp Mask to make the pictures brighter and clear. I uploaded my Photoshop action here.

However, if screenshots taken at night are too bluish, I try to reduce the blue tone using the Color Balance tool and ‘darken’ the pictures using the curve tool.