Most phones have a recovery mode, which, if you damage the software in anyway, allow for the restoration of the original system. You need to open recovery mode before you can repair the system.

Getting into recovery mode is pretty simple, just follow these steps:

http://www.iphone4jailbreak.org/how-to-put-iphone-4-in-dfu-mode.html

After that, it’s required that you download the operating system appropriate to your phone. Make sure it’s the right software:

http://www.redmondpie.com/fix-verizon-iphone-4-stuck-on-apple-boot-logo-loop-when-jailbreaking-ios-4.2.8-with-jailbreakme-3.0/

Good luck!

http://www.tech-exclusive.com/save-ios-4-3-1-shsh-blobs-with-tinyumbrella-4-30-05/

Other related FAQs -

http://www.machackpc.com/what-is-shsh-how-is-it-important-few-faqs/

http://blog.gsmarena.com/heres-a-free-software-method-to-unlock-your-iphone-4s-4-and-3gs/#more-31310

http://www.ifixit.com/Answers/View/5614/iPhone+3G+keeps+turning+off+randomly,+even+with+full+charge…

” i am unsure of your problem but my iphone used to shut off all the time on me until i did this fix which btw i am running IOS5.0.1 firmware on my iphone so the fix may or may not be for all the firmwares but give it a go any way here was my solution:

hello i believe I have finally found a solution to our problem guys and girls so here i will tell you exactly what to do step by step

Step 1. Shut off IPhone Or if your phone Just randomly shut off it may even work both ways i am unsure but try it both ways so if when you see this message your phone has not randomly shut off on its own try shutting it off manually first then if it still has the problem then when it does randomly shut off do as i say.

Step 2. make sure your vibrate switch is set as ring first before you do anything else. once that is done with you are going to do this sequence: switch the vibrate switch in this patter: start off at ring->Vibrate->ring->vibrate… pause for millisecond->Ring-> vibrate then hold the power button and the round button (homebutton) as if you were going to hard reboot the iphone for about 6-8 seconds now my device when i did this part it started up with out me having to let go but for others it should start up as soon as you let go but it seemed to work the way it happened for me although my iphone rebooted after holding those buttons for 3-4 seconds and then imediatly turned off again then i tried it AGAIn and it worked that time and ever since i did this “fix” it has been working fine minus the actual battery drainage software bug for IOS 5.0.1 but it hasnt shutoff on me randomly yet and i have gotten my iphone to finally go down further then 50% so it went to about 45% before i said i needed to charge it so i could use it the next day Hope i helped “

http://www.ifixit.com/Answers/View/5614/iPhone+3G+keeps+turning+off+randomly,+even+with+full+charge…

layfield2 : -

”

i am unsure of your problem but my iphone used to shut off all the time on me until i did this fix which btw i am running IOS5.0.1 firmware on my iphone so the fix may or may not be for all the firmwares but give it a go any way here was my solution:

hello i believe I have finally found a solution to our problem guys and girls so here i will tell you exactly what to do step by step

Step 1. Shut off IPhone Or if your phone Just randomly shut off it may even work both ways i am unsure but try it both ways so if when you see this message your phone has not randomly shut off on its own try shutting it off manually first then if it still has the problem then when it does randomly shut off do as i say.

Step 2. make sure your vibrate switch is set as ring first before you do anything else. once that is done with you are going to do this sequence: switch the vibrate switch in this patter: start off at ring->Vibrate->ring->vibrate… pause for millisecond->Ring-> vibrate then hold the power button and the round button (homebutton) as if you were going to hard reboot the iphone for about 6-8 seconds now my device when i did this part it started up with out me having to let go but for others it should start up as soon as you let go but it seemed to work the way it happened for me although my iphone rebooted after holding those buttons for 3-4 seconds and then imediatly turned off again then i tried it AGAIn and it worked that time and ever since i did this “fix” it has been working fine minus the actual battery drainage software bug for IOS 5.0.1 but it hasnt shutoff on me randomly yet and i have gotten my iphone to finally go down further then 50% so it went to about 45% before i said i needed to charge it so i could use it the next day Hope i helped “

Since you tried to jailbreak it again I’m actually not sure there is any data left on the phone in the first place. 
If your jailbreak requires a firmware to be loaded onto the phone chances are the data is gone. If your jailbreak uses some exploit to “inject” itself into the boot process things shouldn’t have changed.

Since I don’t jailbreak iOS devices that’s pretty much all I know.

MUO Thread about recovering photos from “recovery mode”.
http://www.makeuseof.com/answers/recover-photos-iphone-stuck-recovery-mode/

ZiPhone apparently has an option to “kick it out of recovery mode”.
http://download.ziphone.org/

Since your device is technically jailbroken you might be able to open an SSH connection and backup the photos this way.
http://msftguy.blogspot.com/2012/01/automatic-ssh-ramdisk-creation-and.html