Adding site photos to a print composer atlas in QGIS

I know you mentioned you do not code, but your task may be cumbersome in click and drag software, because you want paired images-filenames; your goal may be accomplished with very few (8 to be precise) lines of code, such as the following; you just install R from https://cran.r-project.org/bin/windows/base/R-4.0.3-win.exe ( I guess you are in windows, in linux there's no escape from coding). R is really easy. I'm using library raster because it was faster than magick and imager libraries.

install.packages("raster")
library(raster) 

# a list of files; pattern is a string you want; 
# full.names parameter is to get the full name with directories
file_list = list.files(path = "/home/elio/Pictures/", pattern = "IMG", full.names = T)

dev.off()                             # to clean before plotting
par(mfrow = c(2,3))                   # 2 rows and 3 columns of plots 
for(i in file_list[1:6]) {            # for loop for the first 6 
temp = brick(i)                         # files are read, replaced at each loop
plotRGB(temp, main = basename(i),   margins = T)   # plotting function
}

It looks like so hard without any script. So I tried a solution like below.

Sample data:

margin and interval

Script:

Copy/paste the script to QGIS Python Editor. Set layout_name, layer_name, path_field, rc, cc and run.

import os
from qgis.PyQt.QtGui import QFont

##### MANUAL SETTINGS #####
layout_name = "LAYOUT_NAME"
layer_name = "Images"
path_field = "img_path"
rc, cc = 2, 2 # rc(row_count), cc(column_count)
interval = 10
margin = 20
###########################

project = QgsProject.instance()

# layout settings
layout_manager = project.layoutManager()
layouts = layout_manager.printLayouts()

# remove the same named layout 
for layout in layouts:
    if layout.name() == layout_name:
        layout_manager.removeLayout(layout)

layout = QgsPrintLayout(project)
layout.setName(layout_name)
layout.initializeDefaults()  

layout_manager.addLayout(layout)
iface.openLayoutDesigner(layout)

layer = project.mapLayersByName(layer_name)[0]
n = layer.featureCount()

### add pages
pcoll = layout.pageCollection()
pc = int(n /(cc*rc)) # required page count
for i in range(pc):
    page = QgsLayoutItemPage(layout)
    page.setPageSize('A4', QgsLayoutItemPage.Landscape)
    pcoll.addPage(page)
###

pw = pcoll.pages()[0].pageSize().width() # page width 
ph = pcoll.pages()[0].pageSize().height() # page height

w = (pw - (cc - 1) * interval - 2* margin) / cc # image width
h = (ph - (rc - 1) * interval - 2* margin) / rc # image height
print(w, h)
for i, f in enumerate(layer.getFeatures()):
    r = (int(i / rc) % cc) # current row number, 0 indexed
    c = i % cc # current column number, 0 indexed
    pn = int(i / (cc * rc)) # current page number, 0 indexed

    # calculate top-left coordinate for the image
    x = margin + c * (interval + w)
    y = margin + r * (interval + h)

    # add image
    img =  QgsLayoutItemPicture(layout)
    img.setPicturePath(f[path_field])
    img.attemptMove(QgsLayoutPoint(x, y, 0), page=pn) 
    img.attemptResize(QgsLayoutSize(w, h, 0))
    img.setFrameEnabled(True)
    img.setPictureAnchor(QgsLayoutItem.Middle)
    layout.addLayoutItem(img)
    
    # calculate top-left coordinate for the label
    x = margin + c * (interval + w)
    y = margin + r * (interval + h) + h

    # add label
    label = QgsLayoutItemLabel(layout)
    label.setText(os.path.basename(f[path_field]))
    label.setFont(QFont('Arial', 14))
    label.adjustSizeToText()
    label.attemptMove(QgsLayoutPoint(x, y, 0), page=pn) 
    label.attemptResize(QgsLayoutSize(w, interval, 0))
    label.setHAlign(Qt.AlignHCenter)
    layout.addLayoutItem(label)

Demo: