This app was mentioned in 23 comments, with an average of 1.61 upvotes
One very useful app for an Android phone is PicSay it allows you to title and paint over pictures and upload them automatically. For iphones you can use Fotovado which does much the same thing. Just take a screen shot of your txt messages and then edit them with one of the apps. Upload them directly to imgur and post the short link here.
Good luck!
In what way do you want to customize them?
Add images and text - Picsay https://play.google.com/store/apps/details?id=com.shinycore.picsayfree
For for - Snapseed https://play.google.com/store/apps/details?id=com.niksoftware.snapseed
For collages - Photo Collage Maker https://play.google.com/store/apps/details?id=com.lyrebirdstudio.collage
Pic Say Pro is a good software to use.
Link to free version: https://play.google.com/store/apps/details?id=com.shinycore.picsayfree
I generally use PicSay for that.
https://play.google.com/store/apps/details?id=com.shinycore.picsayfree
Pic Say is an app that will let you take a photo or pull one from your device, then annotate it. https://play.google.com/store/apps/details?id=com.shinycore.picsayfree