That's awesome! Thank you

Thank you. That is cool looking. But I don't see where to input my array of paths. When I ran the script, it pulls from my camera roll.

Yes, all photos in one view. Just like you see when you use
asset = photos.pick_asset(assets)

If I have the path to several photos on my iphone, for example:

/var/mobile/Media/DCIM/131APPLE/IMG_1415.HEIC
/var/mobile/Media/DCIM/131APPLE/IMG_1412.HEIC
/var/mobile/Media/DCIM/131APPLE/IMG_1389.HEIC
/var/mobile/Media/DCIM/131APPLE/IMG_1388.HEIC
/var/mobile/Media/DCIM/131APPLE/IMG_1373.JPG

How can I show these as thumbnails in a subview?

You're right about the photo ratio. It is doing the right thing.

I've been reading the image section in this doc:
http://omz-software.com/pythonista/docs/ios/ui.html#image
Which I just realized is the general section. But I found the Image module documentation (actually the list of all modules which I haven't seen before). I see that I have a lot to learn. Thanks for all of your help.

That doesn't seem to change anything.

That worked for displaying the photo. How would I resize the frame the same as the photo?

Is this better?

import photos
import ui
from objc_util import *
import csv
import os
#
def open_photo_ref():
    matrix=[]
    my_path=os.path. abspath("photo_file.csv")
    with open(my_path,'r',encoding='utf-8') as reader:
        reader=csv.DictReader(reader)
        for row in reader:
            matrix.append([row['Index'], row['Path']])
    return matrix
#
#
def save_photo(photo_path):
    save_path='/private/var/mobile/Containers/Shared/AppGroup/99B62839-B39E-4ADF-9308-D5D986E28E91/Pythonista3/Documents/Frank/photo_file.csv'
    headings=['Index', 'Path']
    with open(save_path, 'w', newline='',encoding='utf-8') as out_file:
            csv.writer(out_file).writerow(headings)
            new_row = [0, photo_path]
            csv.writer(out_file). writerow(new_row)
    return


#
#              MAIN PROGRAM             #
#
#
w, h = ui.get_screen_size()
h -= 64
bh = bw = 80  # label height and button width 
mg = 10  # margin 
view = ui.View(name='Show Photo', bg_color='#D98880', frame=(0, 0, w, h)) 
#
def photo_action(sender):
    matrix = open_photo_ref()
    row= matrix[0]
    my_path = row[1]
    v = ui.ImageView(frame=(0,0,500,200))
    v.image = ui.Image.named(my_path)
    v.present('sheet')
    return
#
photo_button = ui.Button(frame=(150,10,130,0),border_color='black', border_width=2, corner_radius = 10, tint_color = 'black', background_color='#EAECEE', action=photo_action, font=('Arial Rounded MT Bold',18)) photo_button.title='show'
photo_button.width=100
photo_button.height=40
view.add_subview(photo_button)

#
def pick_action(sender):
    assets = photos.get_assets()
    asset = photos.pick_asset(assets)
    fil = str(ObjCInstance(asset).filename())
    dir = str(ObjCInstance(asset).directory())
    path = '/var/mobile/Media/' + dir + '/' + fil
    path_string = str(path)
    save_photo(path_string)
    return
#
pick_button = ui.Button(frame=(10,10,130,0),border_color='black', border_width=2, corner_radius = 10, tint_color = 'black', background_color='#EAECEE', action=pick_action, font=('Arial Rounded MT Bold',18)) pick_button.title='pick'
pick_button.width=100
pick_button.height=40
view.add_subview(pick_button)

#########################################
nav_view = ui.NavigationView(view)
nav_view.present('sheet')
#########################################

cvp, one more question: I have the following script in which I can pick a photo and save it to a csv file with a button push or show the previously saved photo with the other button push. The only problem is that I haven't been able to change the size or aspect ratio of the displayed photo. I tried setting the frame for the subview and that doesn't seem to work. How can I fix this? Thanks.

import photos
import ui
from objc_util import *
import csv
import os
#
def open_photo_ref():
    matrix=[]
    my_path=os.path. abspath("photo_file.csv")
    with open(my_path,'r',encoding='utf-8') as reader:
        reader=csv.DictReader(reader)
        for row in reader:
            matrix.append([row['Index'], row['Path']])
    return matrix
#
#
def save_photo(photo_path):
    save_path='/private/var/mobile/Containers/Shared/AppGroup/99B62839-B39E-4ADF-9308-D5D986E28E91/Pythonista3/Documents/Frank/photo_file.csv'
    headings=['Index', 'Path']
    with open(save_path, 'w', newline='',encoding='utf-8') as out_file:
            csv.writer(out_file).writerow(headings)
            new_row = [0, photo_path]
            csv.writer(out_file). writerow(new_row)
    return


#
#              MAIN PROGRAM             #
#
#
w, h = ui.get_screen_size()
h -= 64
bh = bw = 80  # label height and button width 
mg = 10  # margin 
view = ui.View(name='Show Photo', bg_color='#D98880', frame=(0, 0, w, h)) 
#
def photo_action(sender):
    matrix = open_photo_ref()
    row= matrix[0]
    my_path = row[1]
    v = ui.ImageView(frame=(0,0,500,200))
    v.image = ui.Image.named(my_path)
    v.present('sheet')
    return
#
photo_button = ui.Button(frame=(150,10,130,0),border_color='black', border_width=2, corner_radius = 10, tint_color = 'black', background_color='#EAECEE', action=photo_action, font=('Arial Rounded MT Bold',18)) photo_button.title='show'
photo_button.width=100
photo_button.height=40
view.add_subview(photo_button)

#
def pick_action(sender):
    assets = photos.get_assets()
    asset = photos.pick_asset(assets)
    fil = str(ObjCInstance(asset).filename())
    dir = str(ObjCInstance(asset).directory())
    path = '/var/mobile/Media/' + dir + '/' + fil
    path_string = str(path)
    save_photo(path_string)
    return
#
pick_button = ui.Button(frame=(10,10,130,0),border_color='black', border_width=2, corner_radius = 10, tint_color = 'black', background_color='#EAECEE', action=pick_action, font=('Arial Rounded MT Bold',18)) pick_button.title='pick'
pick_button.width=100
pick_button.height=40
view.add_subview(pick_button)

#########################################
nav_view = ui.NavigationView(view)
nav_view.present('sheet')
#########################################

Perfect! Thank you!