IrfanView version: 4.52 32bit
OS Version: Windows 10.0.17763 N/A Build 17763

STR:
Run command:
Code:
"C:/Program Files (x86)/IrfanView/i_view32.exe" /scanhidden /dpi=(600,600) /gray /convert=F:\test.bmp
Actual results:
Image size is:
Width: 1700px
Height: 2334px

Click image for larger version. 

Name:	test.bmp(converted to jpg for forum post).jpg 
Views:	30 
Size:	196.1 KB 
ID:	5528

Expected results:
Image size is:
Width: 5100px
Height: 7002px

Click image for larger version. 

Name:	test-good.bmp(converted to jpg for forum post).jpg 
Views:	33 
Size:	1.08 MB 
ID:	5529