I am using Windows 10 with SoapUI 5.5.0 version. I compared the request header in both the tools. The only difference is that in SoapUI there is no boundary end tag and there is binary encoding specified on the form part.
SOAP UI request header -
Accept-Encoding: gzip,deflate
Content-Type: multipart/form-data; boundary="----=_Part_2_1383021.1587674256869"
MIME-Version: 1.0
Content-Length: 695092
Host:XXXXXXXXXXX
Connection: Keep-Alive
User-Agent: Apache-HttpClient/4.1.1 (java 1.5)
------=_Part_2_1383021.1587674256869
Content-Type: image/jpeg
Content-Transfer-Encoding: binary
Content-Disposition: form-data; name="Component_Content"; filename="flower.jpeg"
Postman request header -
Cache-Control: no-cache
Postman-Token: XXXXX
Content-Type: multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxkTrZu0gW
------WebKitFormBoundary7MA4YWxkTrZu0gW
Content-Disposition: form-data; name="Component_Content"; filename="flower.jpg"
Content-Type: image/jpeg
------WebKitFormBoundary7MA4YWxkTrZu0gW--
