Guides
Short, practical how-tos for cleaning up watermarks, backgrounds, and files — using Stelluna's free tools.
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How to Remove a Watermark From a Video
Mark a fixed or semi-transparent logo and have it automatically cleaned up.
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How to Remove Background From a Photo
Upload a photo, get a transparent PNG automatically — no manual selection.
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How to Compress an Image
Shrink a photo's file size in seconds — adjust quality, keep it looking sharp.
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How to Resize an Image
Set an exact width and height in pixels, or scale by percentage — right in your browser.
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How to Upscale an Image with AI
Enlarge a low-resolution photo 4x and sharpen it with AI, right in your browser.
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How to Colorize a Black and White Photo with AI
Bring an old or historical photo to life with realistic AI-generated colors.
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How to Remove an Object from a Photo with AI
Paint over an unwanted object, person, or text and let AI fill in what's behind it.
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How to Find a YouTube Niche Opportunity
Analyze a niche idea's competition, saturation, and CPM potential with real data.
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How to Make a YouTube Thumbnail
Pick a background, add bold text with effects, download a 1280x720 PNG.
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How to Create a QR Code
Paste a link or text, download a custom QR code as PNG or SVG instantly.
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How to Convert a PDF to JPG
Turn every page of a PDF into a JPG image, download one by one or as a ZIP.
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How to Convert Images to PDF
Upload several photos, arrange them, download one combined PDF file.
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How to Merge PDF Files
Upload several PDFs, arrange them, download one combined file.
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How to Split a PDF
Pick the pages you want, download a new PDF with just those.
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How to Organize a PDF
Rotate pages and change their order, download a new file.
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How to Compress a PDF
Pick a quality level, download a smaller file.
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How to Remove or Add a PDF Password
Remove a password you know, or protect a PDF with a new one.
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How to Convert Word to PDF
Upload a .docx file, download it as a PDF.
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How to Convert PDF to Word
Upload a PDF, download it as an editable Word file.
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How to Convert Image Formats
Convert between JPG, PNG, WEBP, HEIC, and AVIF — right in your browser.
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How to Convert Video Formats
Convert between MP4, MOV, and WEBM — right in your browser.
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How to Compress a Video
Pick a quality level, shrink the file size — always outputs MP4.
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How to Trim a Video
Cut just the part you need — set a start and end point, download the clip.
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How to Make a GIF from a Video
Turn a video clip into an animated GIF — pick a width and frame rate.
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How to Convert a Video to MP3
Extract just the audio track from a video — download it as an MP3.
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How to Record Your Screen
Capture your screen, a window, or a tab — no software to install.