Okay, you have plenty of hard drive space; as for your memory (RAM), what did you have open (apps) when you did that screenshot: you are using almost all of the RAM you've got and it is swapping in order to provide memory where you need it. That has to be one of your problems.
thanks for reposting the screenshot - I can see that one!
As long as you're not actively working on the photos, I don't think that has anything to do with a slowdown (except at bootup - as far as I know, the OS treats folders on the desktop as an application that needs to be launched). However, your swaps are absolutely excessive - here is a screenshot of my MBP, also with 4 GB RAM:
As you can see, I have no swaps. Kernel_task uses almost 1 GB RAM (nothing you can do about it - it's the system) and, at the moment, only Firefox is open and is using about 500 MB - that accounts for about 1.5 GB RAM usage. Can you check in your Activity Monitor what is using excessive amounts of RAM.
Not quite sure what I'm looking for or what a swap is. In looking at your shot and then looking at mine, I can certainly see that the difference in your swap and mine is over the top. aloong with Page Ins and Page Outs. I don't know what those are, either. But currently Page ins is running at 9.11 GB, while the Page Outs is 8.62 GB. In looking at the everchaning process screen above it, do I want to cue into the %CPU, the Threads, the Real Mem, or the Virtual Mem? Example: The Safari Web Content is displaying a Real Mem of 234.5 MB, while it is showing 523.8 Virtual Mem.
Can you give me a little more direction? If so, I might be able to articulate what you need better.
To follow up a little more on that, Safari and Safari Web Content are using a total of about 368 MB of real memory, while together they're using over 1 GB of Virtual Memory. iTunes is using 6.4 and 219, respectively, while Mail is using 99 and 295, respectively. Between all of those, you're looking at almost 1.75 GB of Virtual Memory.
Other programs using lots of Virtual Memory are SIMBL Agent (215 MB), storeagent (166 MB), Finder (113 MB), and several dozen using 40-50 MB.
Here's a screenshot of my Activity Monitor showing the two processes which are highest (kernel_task and Firefox) - so scroll through the same window on yours to see which app(s)/processes are using all your RAM.
Here is a good explanation of page ins/outs:
Very simply put: if your RAM is being called on to be in too many places at once, it will keep "swapping" to rush here and there and that will slow things down.
By the way, reading diagnostic reports is not my forte, so hopefully someone else will address that.
Edit: here is another good discussion I found re. swaps/memory:
According to that screenshot, your page outs are almost equal to your page ins. That tells me that you do not have sufficient RAM for the tasks that you are doing, and that this is almost certainly the source of your problems.
There are two solutions to the problem. One is to add more RAM to the machine. That costs money, but would be a good investment, and RAM is relatively cheap.
The other solution is to trim back some of the software you've got running. Etrecheck shows that you have got a LOT of third-party software actively running, and that's going to drive your RAM usage up. Uninstall as much as you can, using the uninstaller provided with the software so that any background processes are removed.
com.logmein.driver.LogMeInSoundDriver Version: 1.0.0
com.Cycling74.driver.Soundflower Version: 1.5.3
com.taoeffect.ispy.kext Version: 2.0.1
com.sophos.kext.sav Version: 8.0.4
Do you actually use LogMeIn? If not, uninstall it. The Soundflower kernel extension has been implicated in kernel panics (a kind of crash) in the past, so I would ditch that. I don't know what "ispy" is, from taoeffect.com, but if you don't use it uninstall it. Regarding Sophos, I'm sure some would tell you to get rid of it unconditionally. I think you probably could get rid of it, but given the amount of third party software you have installed and the fact that you were fooled into installing MacKeeper, it may be a good idea to keep that one.
Then look through the lists below and remove anything you're not using or can live without.
User Login Items:
Rogue Amoeba Schedule Helper
Flip4Mac WMV Plugin.plugin
User Internet Plug-ins:
Google Earth Web Plug-in.plugin
There is no question you installed many third party system modifications, any one of which, or the combination of all, could be responsible for your system performance.
One quick way to check if your User login or launch items are to blame would be to create a new, "temporary" user. Log out of your usual account and log in to the "temporary" one. If your system's behaviour improves, then the culprit(s) lie in the items you selected in System Preferences > Users & Groups, Login Items. Un-check one or more then test the results.
To do this read: Isolating an issue by using another user account
I am unfamiliar with many of your User login items and kernel extensions (GeekTool, ZangZing, PowerboxInjector, RelaunchFinder, Tao Effect, Netculator). For those with which I am familiar, the Western Digital MyBook driver has been implicated in similar problems, so unplug the device to observe any change. If this results in improvement search Western Digital's website for an update.
You can see for yourself Sophos has its tentacles all over your system and could also be a causal factor. Anything that modifies your system has the potential to affect its performance. The decision to use such utilities is yours but it must be accompanied with the awareness of how it works, what benefit it conveys, and the limitations inherent in its design. Given the fact that the threat of Mac malware is so minimal, you have to question its value. Sophos did nothing to prevent you from installing the execrable MacKeeper or many system hacks that can contribute to system instability, slowdowns, and crashes - nothing can do that except you.
Simply stating that you don't have enough RAM is incomplete. It is better stated your Mac may have inadequate resources to run acceptably, given all the modifications with which you have burdened it.
For example, here is the applicable EtreCheck excerpt for my MacBook Air, which also has 4 GB RAM:
Problem System Launch Daemons:
Problem System Launch Agents:
User Launch Agents:
User Login Items:
3rd Party Preference Panes:
User Internet Plug-ins:
1.7 % WindowServer
0.8 % EtreCheck
0.6 % System
0.6 % activitymonitord
0.4 % hidd
0.4 % Safari
0.1 % fontd
0.1 % coreservicesd
0.0 % mds
0.0 % Activity
The above system runs fast with no objectionable slowdowns, even after loading nearly every RAM-intensive program I have installed: Safari, iMovie, iTunes, iPhoto... many others too numerous to mention. I have tried and failed to find limitations that would make it run unacceptably slow, but I use almost no third party system hacks.
More RAM is always better but adding more would be masking a symptom instead of fixing the problem. The problem is not Mountain Lion. Fix the problem.