Hi @cjs321 ,
Do you want to send email with images from gallery in PowerApps?
If so, you do not need to call flow in PowerApps.
You could make this directly in PowerApps.
I've made a similar test for your reference:
1)save your images in an excel table
If you want to save images in excel, you need to insert a column named fieldname [image]
In my test, I insert a column named: Image [image]
Then upload this excel file in one drive.
(PowerApps could only connect with excel in one drive, can not connect with images in one drive.)
2)connect your app with this excel table in one drive
3)display these images in a gallery
set the gallery's Items to this table
set the image's Image inside the gallery:
ThisItem.Image
4)set the send email button's OnSelect:
Office365Outlook.SendEmailV2(To,subject,body,{Attachments:
Table(
{Name:"image1.jpg",ContentBytes:First(FlooringEstimates).Image , '@odata.type':"",IsHtml:true},{Name:"image2.jpg",ContentBytes:Last(FirstN(FlooringEstimates,2)).Image ,
'@odata.type':"",IsHtml:true},{....}
)
}
)
You could replace the image names that you want. In the example, I use image1.jpg and image2.jpg.

Here's a similar issue for your reference:
https://powerusers.microsoft.com/t5/Building-Power-Apps/send-image-via-email/td-p/103464
Best regards,