Client asked for thermal imaging in an effort to locate a chronic water intrusion source. Rain water leakage occurs during certain wind driven conditions. Several contractors have attempted to “fix” the problem, one did re-install new Tyvek and flashing. Of course, I could not see any of the window flashing behind aluminum siding. No abnormal infrared conditions observed, but did record high moisture readings at the exterior window composite trim. Trim was replaced 5 years ago, Z flashing is present. My recommendation is to remove a section of siding to evaluate the flashing. Any other suggestions? 
Looks like windows components are made of wood and are starting to deteriorate, caulk was improperly applied… I wish you had more detailed pictures of the window sill, cant tell how they applied the flashing around the sill, if it butts to it or under…???..tell us more about the window components.
Outside of that, the only way to truly fix it is to remove everything around the window, properly flash around the flanges themselves (flashing tape) and reinstall siding and flashing. The z flashing is probably not adequate or properly installed… one would be best to have the siding contractor bend his own flashing. Last week I was called to fix a similar problem over a self retracting roof of a pool house…I did my own flashing paying attention to making a proper drip edge… no reported problems since it rain over the weekend.
Jeff
Looking at page 3 left sill area it seems wide open and not even caulked properly.
Is that trim angled up to catch water?
If you were called just to inspect that, that’s a job I would have declined. No inspection is necessary. A complete re-do is called for. Insulation and interior wall cavities may be ruined as well. Can you say “mold farm”?
Joe,
I was asked to do a specific thermal inspection, which is not unusual. You are correct, another redo will be required. Am attaching a few more images. 
Does not look like there are ( any ) backer rod and sealant joints between the windows and trim. For starters!
As per most window mfgrs. specs.