The Latitude 7290 has an Intel 7th Generation Processor. Intel and Microsoft (and hence Dell) only support Windows 7 on up to 6th Generation Processors so there will be no ISO for that model.
https://www.dell.com/support/article/uk/en/ukbsdt1/sln300777/dell-support-for-windows-7-and-8-1-on-the-skylake-chipset?lang=en
Note Windows 7 reaches End of Life next month.