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Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →Outbyte PC Repair FREEClear out junk files and repair common Windows errorsFree Scan →To capture a full-page screenshot after lazy-loaded images have had a chance to load, scroll through the page to trigger them, wait for image completion, then use Firefox WebDriver’s documented full-page screenshot method. Selenium’s ordinary screenshot method captures the current window, not necessarily the whole document.
What you need
- Python and Selenium installed in an environment with Firefox and a compatible Firefox WebDriver available.
- A target page you are permitted to automate and capture.
The Firefox Python API documents save_full_page_screenshot(path) and get_full_page_screenshot_as_png() for full-document PNG captures. The documented API is browser-specific; do not assume it works the same way in other browsers. See the Selenium Firefox WebDriver API.
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Run this Python example
Install Selenium with python -m pip install selenium. The example scrolls in viewport-sized steps, waits for image load attempts to complete, checks whether the document height has stabilized, and saves a full-page PNG through Firefox.
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from selenium import webdriver
from selenium.webdriver.support.ui import WebDriverWait
URL = "https://example.com"
OUTPUT = "page.png"
options = webdriver.FirefoxOptions()
# Optional: headless mode, if supported in your Firefox environment.
# options.add_argument("-headless")
driver = webdriver.Firefox(options=options)
try:
driver.get(URL)
# Scroll down by about one viewport at a time. This brings native
# loading="lazy" images near the viewport so the browser can fetch them.
previous_height = 0
stable_passes = 0
while stable_passes < 2:
height = driver.execute_script("return document.documentElement.scrollHeight")
viewport = driver.execute_script("return window.innerHeight")
y = 0
while y < height:
driver.execute_script("window.scrollTo(0, arguments[0])", y)
time.sleep(0.2)
y += max(viewport, 1)
driver.execute_script("window.scrollTo(0, document.documentElement.scrollHeight)")
# Wait until each image's load attempt has completed. This does not
# guarantee success: a failed image can also have complete === true.
WebDriverWait(driver, 30).until(
lambda d: d.execute_script(
"return Array.from(document.images).every(img => img.complete)"
)
)
new_height = driver.execute_script("return document.documentElement.scrollHeight")
if new_height == previous_height:
stable_passes += 1
else:
stable_passes = 0
previous_height = new_height
# Optional diagnostic: identify completed images that appear not to have loaded.
failed_images = driver.execute_script(
"return Array.from(document.images)"
".filter(img => img.complete && img.naturalWidth === 0)"
".map(img => img.currentSrc || img.src)"
)
if failed_images:
print("Images that may have failed:", failed_images)
driver.save_full_page_screenshot(OUTPUT)
print(f"Saved full-page screenshot to {OUTPUT}")
finally:
driver.quit()Replace https://example.com with the page to capture. The loop makes two passes with an unchanged document height before capture, which helps catch pages that grow as content is revealed. It is a practical stability check, not a guarantee that every site’s scripts or visual updates have finished.
#1 Best Overall
Why the order matters
Navigation returning is only an initial readiness point
driver.get() waits according to the page-load strategy and document readiness setting, but dynamically updated applications can continue to change afterward. Selenium cautions that a document reaching readyState complete does not necessarily mean a single-page application has finished loading. See Selenium browser options and page-load strategies.
Scrolling triggers native lazy loading
Browsers defer fetching native lazy-loaded resources until they are near the viewport. Scrolling down through the document is therefore important: a fixed wait while parked at the top may leave off-screen images unfetched. See MDN’s lazy-loading overview.
Completion does not mean success
An image’s complete property indicates that its load attempt has completed, including cases where it failed. Checking naturalWidth helps flag images with no successfully decoded intrinsic width. See MDN’s HTMLImageElement.complete reference.
Choose the right screenshot method
| Method | What it captures | When to use it |
|---|---|---|
Firefox save_full_page_screenshot() |
Full document as PNG | Use when running Firefox WebDriver and you need a documented native full-page capture. |
| Ordinary WebDriver screenshot | The current browser window | Use for the visible viewport; do not assume it includes the entire document. See Selenium Remote WebDriver API. |
| Other browser-specific or stitched capture | Depends on browser and implementation | Verify the current official browser and driver documentation, and test the result on your page. |
Adjust the wait for dynamic pages
The sample waits until every image currently in document.images reports completion. For a page with images inserted later by application code, a one-time image check may run before those elements exist. The repeated scroll-and-height pass helps with pages that reveal more content as you move, but it cannot identify every site-specific “finished” condition.
- If the page has a known element that appears only when content is ready, wait for that element with Selenium’s explicit waits before capture.
- If the page inserts content after a user action, automate that action before scrolling.
- If the page continues adding content, use a page-specific condition rather than extending a generic sleep indefinitely.
- For pages with unusually tall documents, check that the resulting image contains the expected beginning and end of the page.
Troubleshooting
The image is only the visible window
You may be using Selenium’s ordinary screenshot method, which is documented as a current-window capture. Run the capture in Firefox and call save_full_page_screenshot(); verify Firefox WebDriver is the active driver.
Images are missing near the bottom
Make sure the script scrolls to the bottom before waiting. Some pages add new sections as the viewport moves; repeat scrolling after document height grows and use a page-specific readiness condition if needed.
The script times out waiting for images
An image request may never complete, or the page may keep inserting images. Inspect the page and the browser’s network/console diagnostics, then narrow the wait to images relevant to the capture or define a site-specific timeout policy. Do not treat a timeout as proof that all images are broken.
An image is complete but appears broken
Check naturalWidth as in the example. A completed request can still fail, so distinguish “finished attempting to load” from “loaded successfully.”
The page changes after the wait
Navigation completion and image completion do not cover all application-driven updates. Wait for a known page-specific signal, repeat the scroll pass if content height changes, and inspect the final screenshot for sticky elements or content that appeared late.
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ScreenshotNeo provides a screenshot API and MCP server. Its capture options can remove cookie/consent banners, newsletter popups, and chat widgets before the shot; bot checks, blank pages, failed loads, timeouts, and cache hits are not billed. AI agents can take screenshots through its MCP server. The free plan includes 1,000 screenshots per month with no card; paid plans start at $5 for 3,000.
For a direct PNG/WebP/PDF capture, see the ScreenshotNeo API documentation. Example cURL request:
Do these 3 things before closing this tab:
1Scan for outdated or missing drivers - takes under a minute2Repair Windows errors before they cause bigger problems3Fix the driver behind crashes, sound loss and screen glitchescurl -G "https://api.screenshotneo.com/v1/shot" -d access_key=YOUR_API_KEY --data-urlencode url=https://example.com -o shot.webpSign up for ScreenshotNeo’s free plan: 1,000 screenshots a month, no card required.
Frequently Asked Questions
Can Selenium capture a full-page screenshot in Chrome with the same method?
The documented Python full-document methods covered here are Firefox WebDriver methods. Check the current official documentation for the browser and driver you intend to use rather than assuming the Firefox API is portable.
Does scrolling guarantee every image and widget has finished rendering?
No. It triggers viewport-based native lazy loading, but application scripts and site-specific interactions can continue changing the page. Use a page-specific readiness condition when needed.
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