After working on this problem i managed to solve it.
So basically, there are 2 problems:
1. We dont know path to real image files;
2. Wikitree and Myheritage expect different Gedcom tags with images.
Hopefully in future developers will resolve issue - on both on myheritage and wikitree. Right now here is good workaround:
1. For each Wikitree individual - simply edit Photo Title: to be "Some Existing title FILE path_to_real_image_taht_works_in_incognito_window". For living people this could be link to thumbnail on wikitree or link to geni thumbnail (which is larger). Thats all for profiles with images to be done.
2. Then when exporting gedcom we will see dollowing tags:
2 FORM Image
2 FILE https://www.WikiTree.com/wiki/Image:somebody-1.jpg
2 TITL Nice Title FILE http://someresource.com/image1.jpg
Plese note, link can be inside or outside of wikitree, doesnt matter.
3. Then we need manually to convert this "incompatible tags format" to expected by MyHeritage:
2 FORM jpg
2 _PRIM Y
To do this automatically i wrote following vbs script:
txtfile = "OurFamilyTree_fromWikitree.ged"
newfile = "OurFamilyTree_fromWikitree_imagefix.ged"
Dim objStream, strData
Set objStream = CreateObject("ADODB.Stream")
objStream.CharSet = "utf-8"
strData = objStream.ReadText()
arrText = Split(strData, vbLf)
For i = 0 To UBound(arrText) - 1
strLine = arrText(i)
If InStr(strLine," FILE http") > 2 Then
strline = "2" & mid(strline,InStr(strLine," FILE http"))
strline = "2 FORM Image" & vbLf & strline
strline = strline & vbLf & "2 FORM jpg"
strline = strline & vbLf & "2 _PRIM Y"
strNewText = strNewText & strLine & vbLf
Set objStreamWrite = CreateObject("ADODB.Stream")
objStreamWrite.CharSet = "utf-8"
objStreamWrite.SaveToFile newfile, 2