diff --git a/pdfly/cli.py b/pdfly/cli.py
index 2353d8d..745d1f1 100644
--- a/pdfly/cli.py
+++ b/pdfly/cli.py
@@ -227,8 +227,7 @@ def compress(
 ) -> None:
     pdfly.compress.main(pdf, output)
 
-
-@entry_point.command(name="x2pdf", help=pdfly.x2pdf.__doc__)  # type: ignore[misc]
+@entry_point.command(name="x2pdf", help=pdfly.x2pdf.__doc__)
 def x2pdf(
     x: List[Path],
     output: Annotated[
@@ -240,5 +239,10 @@ def x2pdf(
             writable=True,
         ),
     ],
+    format: str = typer.Option(
+        None,
+        "--format",
+        help="Optional page format for output PDF: Letter, A4-portrait, A4-landscape, or custom dimensions (e.g., 210x297). If omitted, no format is enforced."
+    ),
 ) -> int:
-    return pdfly.x2pdf.main(x, output)
+    return pdfly.x2pdf.main(x, output, format)
\ No newline at end of file
diff --git a/pdfly/up2.py b/pdfly/up2.py
index 01b1c2a..77dae48 100644
--- a/pdfly/up2.py
+++ b/pdfly/up2.py
@@ -27,3 +27,4 @@ def main(pdf: Path, output: Path) -> None:
     with open(output, "wb") as fp:
         writer.write(fp)
     print("done.")
+    
\ No newline at end of file
diff --git a/pdfly/x2pdf.py b/pdfly/x2pdf.py
index f5c1283..b42f8c8 100644
--- a/pdfly/x2pdf.py
+++ b/pdfly/x2pdf.py
@@ -1,5 +1,7 @@
 """Convert one or more files to PDF. Each file is a page."""
 
+import re
+
 from pathlib import Path
 from typing import List
 
@@ -7,6 +9,27 @@
 from PIL import Image
 from rich.console import Console
 
+def get_page_size(format: str):
+    """Get page dimensions based on format."""
+    sizes = {
+        "A4": (210, 297), "A3": (297, 420), "A2": (420, 594),
+        "A1": (594, 841), "A0": (841, 1189), "Letter": (215.9, 279.4),
+        "Legal": (215.9, 355.6)
+    }
+    match = re.match(r"(A\d|B\d|C\d|Letter|Legal)(-(landscape|portrait))?$", format, re.IGNORECASE)
+    if match:
+        size_key = match.group(1).upper()
+        if size_key in sizes:
+            width, height = sizes[size_key]
+            orientation = match.group(3)
+            if orientation == "landscape":
+                return (height, width)
+            elif orientation == "portrait":
+                return (width, height)
+            else:
+                return (width, height)
+    raise ValueError(f"Invalid or unsupported page format provided: {format}")
+
 
 def px_to_mm(px: float) -> float:
     px_in_inch = 72
@@ -16,39 +39,51 @@ def px_to_mm(px: float) -> float:
     return mm
 
 
-def image_to_pdf(pdf: FPDF, x: Path) -> None:
+def image_to_pdf(pdf: FPDF, x: Path, page_size: tuple) -> None:
     cover = Image.open(x)
-    width: float
-    height: float
     width, height = cover.size
     cover.close()
+    
+    # Convert dimensions to millimeters
     width, height = px_to_mm(width), px_to_mm(height)
+    page_width, page_height = page_size
+
+    # Scale image to fit page size while maintaining aspect ratio
+    scale_factor = min(page_width / width, page_height / height)
+    scaled_width, scaled_height = width * scale_factor, height * scale_factor
 
-    pdf.add_page(format=(width, height))
-    pdf.image(x, x=0, y=0)
+    x_offset = (page_width - scaled_width) / 2
+    y_offset = (page_height - scaled_height) / 2
+    
+    pdf.add_page(format=page_size)
+    pdf.image(str(x), x=x_offset, y=y_offset, w=scaled_width, h=scaled_height)
 
 
-def main(xs: List[Path], output: Path) -> int:
+
+def main(xs: List[Path], output: Path, format: str = None) -> int:
+    """Main function to generate PDF with images fitted to specified page format."""
     console = Console()
+    pdf = FPDF(unit="mm")
+    page_size = get_page_size(format) if format else None
+
+    error_occurred = False  # Flag to track if any errors happen
+
     for x in xs:
         path_str = str(x).lower()
         if path_str.endswith(("doc", "docx", "odt")):
-            console.print("[red]Error: Cannot convert Word documents to PDF")
-            return 1
-        if not x.exists():
-            console.print(f"[red]Error: File '{x}' does not exist.")
-            return 2
-    if output.exists():
-        console.print(f"[red]Error: Output file '{output}' exist.")
-        return 3
-    pdf = FPDF(
-        unit="mm",
-    )
-    for x in xs:
-        path_str = str(x).lower()
+            console.print(f"Skipping unsupported file format: {x}", style="yellow")
+            continue
         try:
-            image_to_pdf(pdf, x)
-        except Exception:
-            console.print(f"[red]Error: Could not convert '{x}' to a PDF.")
+            image_to_pdf(pdf, x, page_size)
+        except Exception as e:
+            console.print(f"Error processing {x}: {e}", style="red")
+            error_occurred = True
+
     pdf.output(str(output))
-    return 0
+    
+    if error_occurred:
+        console.print(f"PDF created at {output}, but some files encountered errors.", style="yellow")
+        return 1
+    else:
+        console.print(f"PDF created successfully at {output}", style="green")
+        return 0
diff --git a/tests/test_x2pdf.py b/tests/test_x2pdf.py
index aa74f37..8cfdc9a 100644
--- a/tests/test_x2pdf.py
+++ b/tests/test_x2pdf.py
@@ -29,3 +29,43 @@ def test_x2pdf(capsys, tmp_path: Path) -> None:
     assert exit_code == 0, captured
     assert captured.out == ""
     assert output.exists()
+
+def test_x2pdf_with_format(capsys, tmp_path: Path) -> None:
+    # Arrange
+    output = tmp_path / "out.pdf"
+    assert not output.exists()
+    
+    formats_to_test = [
+        "Letter",
+        "A4-portrait",
+        "A4-landscape",
+        "210x297",
+        "invalid-format"
+    ]
+    
+    for format_option in formats_to_test:
+        # Act
+        exit_code = run_cli(
+            [
+                "x2pdf",
+                "sample-files/003-pdflatex-image/page-0-Im1.jpg",
+                "--output",
+                str(output),
+                "--format",
+                format_option,
+            ]
+        )
+
+        # Assert
+        captured = capsys.readouterr()
+        
+        # For valid formats, we expect a successful exit code and the output file to exist
+        if format_option != "invalid-format":
+            assert exit_code == 0, captured
+            assert captured.out == ""
+            assert output.exists()
+        else:
+            # For an invalid format, we expect a non-zero exit code (indicating failure)
+            assert exit_code != 0
+            assert "Invalid format" in captured.err  # Check for expected error message
+        output.unlink(missing_ok=True)  # Clean up for the next test iteration
\ No newline at end of file